IMO, B is the right answer as E is wordy. The fragment "this is because" doesn't say anything actually.

SmarpanGamt wrote:The relationship between cell phone use and the incidence of brain tumors is still unclear, this is because some studies show a causal relationship while others do not.

is still unclear, this is because some studies show
is still unclear; some studies show
are still unclear because some studies show
is still unclear because: some studies show
is still unclear; the reason is that some studies show

The first option solves the problem of comma splice by introduction of conjuction. Please explain Y this choice is incorrect. Also explain your bet.

B seems to be disjointed. In E, The Second part of the sentence clearly states it is the reason for the relationship not being clear which is missing in B.

Please clarify based on my argument above as I am still unsure with the choices between B and E ..

IMO B

B is the right answer.. E is wordy

B.

A semi-colon must connect independent clauses on either side. E fails that criterion.

According to me the answer is C because two subjects joined by and will take plural verb that is are.

I am surprised to see that this question is from Mgmat !!
The options in consideration are B and E. Rest of the options have valid reasons to eliminate.

Now we should subordinate one clause to the other as we want to show why the relationship between.... is unclear..This can be achieved by having a subordinate clause at the end of the first clause introduced by because and then stating the reason as to why the relationship is unclear...

Now, with option B, the intent of showing WHY the relationship is unclear is lost as we have two independent clauses separated by a semicolon... As a reader I do not think we come to know that the second independent clause is a reason for the first clause...

The best option could have been -> is still unclear because some studies show
D gets close to the ideal option but is wrong for using colon...
I agree that option E is wordy for using the reason is that..
I also know that GMAT always asks us to select the BEST of the answer choices but I did not find any BEST option here...B is better but not best... After going through official questions, the correct option pops out in front of your eyes and is crystal clear.. You can not question the correct answer...

But this is not the case here..I m eager to get experts opinion over here !!

I kinda agree with adi_800.

I hope Ron replies here. I will send him a PM.

I need a clarification b/w B & E . My vote was for E.

I thought a semi colon is used when a sentence can be an independent sentence if separated ie.

Sentence 1 -The relationship between cell phone use and the incidence of brain tumors is still unclear.
Sentence 2- The reason is that some studies show a causal relationship while others do not.

Can somebody please explain why E is wrong & B is correct in detail.

You can see 1 post up. Ron has explained why option B is correct.

lunarpower wrote:Now, with option B, the intent of showing WHY the relationship is unclear is lost as we have two independent clauses separated by a semicolon... As a reader I do not think we come to know that the second independent clause is a reason for the first clause...

the sentence doesn't actually explain why the relationship is unclear; it states something that emphasizes, but does not explain, the fact that the relationship is unclear (i.e., studies are giving apparently contradictory results).

that's about the only way i can explain, but i can give an analogy:
we don't yet know which candidate is going to win the election; one major poll predicted that candidate x would win, while another predicted that candidate y would win.
--> in this sentence, you could not replace the semicolon with comma + "because", because the two clauses don't describe a cause-and-effect relationship. the contradictory poll results just underscore the fact that we don't know which candidate will win, but they do nothing to explain why that uncertainty exists.
the same is happening in the problem at hand.

I guess this is one of the GMAT's latest questions where the importance is given to which sentence coneys the message "Effectively". Two sentences are grammatically correct but one is right on effectiveness.

I went for E too :!:

Samuel

i chose the option E can anyone explain how B is much better choice than E as it sounds more concise to me

Tough one indeed, i chose E!
Not able to compromise with B