Correct answers:
[spoiler]1. a
2. c
3. b[/spoiler]

Doubts:
1. Why B is incorrect
2. Why B is incorrect
3. Why A is incorrect... isn't "opinion on" correct idiom?

well in 3rd SC even i reckon "opinion on" is the right idiom....but the issue that arises is the usage of "like".. "Such ...as" is the right usage for giving examples....

PAB2706 wrote:well in 3rd SC even i reckon "opinion on" is the right idiom....but the issue that arises is the usage of "like".. "Such ...as" is the right usage for giving examples....

I agree with you but the correct ans choice doesn't use "such as" either

it does....

SUCH fundamentally important bla bla bla AS

"opinion on" is wrong in this particular context. The intention of that sentence is that people could shape opinios in area X, Y, Z. And not ON area X,Y,Z ("What is your opinion on X?").

PAB2706 wrote:it does....

SUCH fundamentally important bla bla bla AS

Sounds correct but this poses another question. Are both of these sentences correct?

Such fundamentally important areas as....
Fundamentally important areas such as....

for 1st A is correct ( comparison word AS and THAN does not req verb to be repeaated )
B is in correct bcoz of absence of verb were.

For 2nd there is no comparison being done so we dont need as or than

for 3rd i think all the choices are having some issues but In GMAT sometime we have to chose Best in the worst.
A)like is used for giving example...wrong need such as
B)except opinion in everything luks fine so keep it
C)again like used for giving eg. wrong
D)the shaping of public opinion for luks wordy
E)its wordy and opinion around is definitely wrong.

and for your doubt on
Sounds correct but this poses another question. Are both of these sentences correct?

Such fundamentally important areas as....
Fundamentally important areas such as....

i think both are correct but i will Prefer B for being straightness.... and rest depends on the context of the sentence

Someone please explain the reason behind OAs for 1st and 2nd..

as far as 2nd is considered, I read somewhere about the thumb rule..whenever 'times' is used 'as' should follow.. but it appears the thumb rule doesn't fit here..

when to use 'as', 'that','than'..?

For the 1st..i'm listless to remove even a single choice out of scope..

I think the explanation is:

Ques. 1:

b "than born" shows comparison of babies rather than women
c out of scope as it misses verb in subordinate clause i.e. than they were
d and e - incorrect use of past perfect as both types of women i.e. under 30 and over 30 gave birth in the same period of time.
a correctly compares women under and over 30

Ques. 2.:
I think confusion might be between b and c. b is wrong as no comparison is made between prices of two things. and that is suitable in this context.

Any suggestions are most welcome