Sentence Correction

Can someone please help me with the fol OG 12 SC questions, I could not understand OG's explanation for these. Thanks a ton in advance
1. Ans is D, I did not understand the verb tense used here, how does 'falling' represent an activity of past?
The results of the company's cost-cutting measures
are evident in its profits, which increased 5 percent
during the first 3 months of this year after it fell over
the last two years.
(A) which increased 5 percent during the fi rst
3 months of this year after it fell
(B) which had increased 5 percent during the fi rst
3 months of this year after it had fallen
(C) which have increased 5 percent during the fi rst
3 months of this year after falling
(D) with a 5 percent increase during the fi rst
3 months of this year after falling
(E) with a 5 percent increase during the fi rst
3 months of this year after having fallen

2. 73. Combining enormous physical strength with higher
intelligence, the Neanderthals appear as equipped for
facing any obstacle the environment could put in their
path, but their relatively sudden disappearance during
the Paleolithic era indicates that an inability to adapt
to some environmental change led to their extinction.
(A) appear as equipped for facing any obstacle the
environment could put in their path,
(B) appear to have been equipped to face any - why have been-present perfect
obstacle the environment could put in their path,
(C) appear as equipped to face any obstacle the
environment could put in their paths,
(D) appeared as equipped to face any obstacle the
environment could put in their paths,
(E) appeared to have been equipped for facing any
obstacle the environment could put in their path,
Correct ans is B, again i am facing difficulty in understanding the verb form

3. According to some analysts, the gains in the stock
market reflect growing confidence that the economy
will avoid the recession that many had feared earlier in
the year and instead come in for a "soft landing,"
followed by a gradual increase in business activity.

(A) that the economy will avoid the recession
that many had feared earlier in the year and
instead come
(B) in the economy to avoid the recession, what
many feared earlier in the year, rather to come
(C) in the economy's ability to avoid the recession,
something earlier in the year many had feared,
and instead to come
(D) in the economy to avoid the recession many
were fearing earlier in the year, and rather
to come
(E) that the economy will avoid the recession that
was feared earlier this year by many, with it
instead coming
How would you attack this question?

4. Because an oversupply of computer chips has sent
prices plunging, the manufacturer has announced that
it will cut production by closing its factories for two
days a month.
(A) Because an oversupply of computer chips has
sent prices plunging,
(B) Because of plunging prices for computer chips,
which is due to an oversupply,
(C) Because computer chip prices have been sent
plunging, which resulted from an oversupply,
(D) Due to plunging computer chip prices from an
oversupply,
(E) Due to an oversupply, with the result that
computer chip prices have been sent plunging, --- what else could be the reason to choose ans choice A other than that explined in OG- chronological order