Critical Reasoning

Archaeologists in Michigan have excavated a Native American camp near Dumaw Creek. Radiocarbon dating of animal bones found at the site indicates that the camp dates from some time between 1605 and 1755. However, the camp probably dates to no later than 1630, since no European trade goods were found at the site, and European traders were active in the region from the 1620's onward.

Which of the following, if true, most strengthens the argument?

(A) Due to trade among Native Americans, some European trade goods would have reached the area before the European traders themselves did.

(B) At all camps in the region that have been reliably dated to the late 1620's, remains of European trade goods have been found.

(C) The first European trade goods to reach the area would have been considered especially valuable and preserved as much as possible from loss or destruction.

(D) The first European traders in the area followed soon after the first European explorers.

(E) The site is that of a temporary camp that would have been used seasonally for a few years and then abandoned.

following is my doubt :
i somewhere feel that my comprehension of B is confusing me !!
B says :At all camps in the region that have been reliably dated to the late 1620's, remains of European trade goods have been found.

now what is disturbing me is the phrase dated to the late 1620's
what does it mean ? to me it means the following dates :1625 ;1626;1627;1628 and 1629
though i feel that if that is what that phrase in B meant then its getting somewhat difficult to appreciate B as an answer
however if that phrase in B meant all the years later of 1620 till, lets say, 1755 then i can understand how B is the answer
i strongly feel that the language of B should have been as follows :
At all camps in the region that have been reliably dated 1620 onwards , remains of European trade goods have been found.
if i am not able to put across my doubt to u then plz read the following
to me the following sentence : i was in Vegas in late 1990's means that i was in Vegas somewhere in 1995 to 1999 not 1990 onwards !!
similarly in option B : the phrase "late 1620 " means from 1625 to 1629
i feel that this phrase sud have been later of 1620 or 1620 onwards

PS : i am not questioning the OA .plz correct me if my comprehension of that phrase (late 1620's ) is faulty .
pls help me understand
thanks and regards
aditya

thanks sir for ur prompt reply
u said i quote :

I realize this is a bit of a leap ("What if it was just the late 1620s, then it stopped?"), but it's not too much of a leap. After all, we've already been told that European traders were active in the region from the 1620s onward

honestly it was this leap that kept me puzzled and i thought that may be my comprehension is wrong.but even if we are told that European traders were active in the region from the 1620s onward how does it proves that B's implied meaning is that goods were also found even after 1630 in all the sites that were reliably dated ,after all the reliably dating that B suggest is only for the date 1625 to 1629 .
thanks and regards
aditya

Is this an official Question?

I too contend about the OA - B. Though, on first glance, i struck C out, I finally concluded C must be answer and here's why:

Stem:
Camp must be from 1605 - 1755; camp does not have goods from 1920s; European trades are active from 1920s
Conclusion: So, camp must be before 1930s.

Stem analysis: What if such trade goods were destroyed or perishable? At the beginning, the trade could have included goods that are of above mentioned nature? Then, the entire conclusion will go for
a toss. So, the conclusion must have assumed that such trades had not happened. => We see goods from 1920's and only from 1920's only trades must have occurred. (that forms the whole basis of conclusion)


(A) Due to trade among Native Americans, some European trade goods would have reached the area before the European traders themselves did.


(B) At all camps in the region that have been reliably dated to the late 1620's, remains of European trade goods have been found.
european goods found to be used in late 1620's. Stem concludes, camp must be from < 1630. If this were the assumption, the stem must have concluded comfortably "camps were before late 1920's...

(C) The first European trade goods to reach the area would have been considered especially valuable and preserved as much as possible from loss or destruction.
Seems to agree with the analysis.

(D) The first European traders in the area followed soon after the first European explorers.
The stem does not talk about european explorers
(E) The site is that of a temporary camp that would have been used seasonally for a few years and then abandoned.

I will write my idea. pls , comment on my following.

this passage is typical of one kind of cr questions in og. In this kind of question, 2 event are presented and the conclusion is that 2 events are relevant. The 2 events here are: the camp has not european goods and the european trade began in 1960s. The conclusion here is that the camp dates 1920s/1930.

this type of argument is popular in og books. this type of argument appears at the end of og books. the question for this type is strengthening. I do not see weakening question for this type.

My approch:
after understand the argument , my goal is looking for information which increase the bond between 2 events.
going to answer choices, I see B match.

if we approach as I do above, this type of questions becomes easy.

here I have problem, and want you, experts comment.

there is another approach.
because this is a strengthening question, some experts advise us to prethink an assumption and look for information in answer choices which increase the belief in that assumption.

but I can not prethink assumption. I can not follow this approach.
what is the assumption here, and what is the information which strengthen that assumption.

the point I want you to discuss is that if we follow the my approach, this question become simple. if we follow the approach of prethinking assumption, we are stuck at prethinking an assumption.

HOW do we solve this situation? pls comment. thank you.