Sentence Correction

Q To develop more accurate population forecasts, demographers have to know a great deal more than now about the social and economic determinants of fertility.

A. have to know a great deal more than now about the social and economic
B. have to know a great deal more than they do now about the social and economical
C. would have to know a great deal more than they do now about the social and economical
D. would have to know a great deal more than they do now about the social and economic
E. would have to know a great deal more than now about the social and economical

i think its D. wats the ans

economicle is not logic inhere

comparison requires verb to make elements compared clear

D is right

ILULA08 wrote:Q To develop more accurate population forecasts, demographers have to know a great deal more than now about the social and economic determinants of fertility.

A. have to know a great deal more than now about the social and economic
B. have to know a great deal more than they do now about the social and economical
C. would have to know a great deal more than they do now about the social and economical
D. would have to know a great deal more than they do now about the social and economic
E. would have to know a great deal more than now about the social and economical

Choice D

B, C, E out for wrong usage of economical when it should be "economic".

A & D Left...

A) to know a great deal more than now is awkward because it reads that the demographers have to "know a great deal" compared to "more" than "now".

Choice D) is parallel and clear.

Actually I also chose D but surprisingly found E as the answer. It was from a paper based test. I think the answer is wrong which is confirmed here

Thanks

why not B?

This question is from OG 12. So you can't say that the answer is wrong.

But my question is why WHOULD HAVE TO KNOW is right? I believe, "To develop something... scientists HAVE TO KNOW".