Sentence Correction

Hi,

I thought the answer was D but actually is C. Can anyone explain why D is wrong??? Thank you!!



According to Interstudy, a nonprofit organization that studies health maintenance organizations (HMO’s), they estimate that, in comparison to last year, when only 36 percent of the nation’s 607 HMO’s was profitable, this year 73 percent will be.

(A) they estimate that, in comparison to last year, when only 36 percent of the nation’s 607 HMO’s was profitable, this year 73 percent will be

(B) compared to only 36 percent of the nation’s 607 HMO’s being profitable last year, they estimate 73 percent would be this year

(C) only 36 percent of the nation’s 607 HMO’s were profitable last ye
ar; it estimates that this year 73 percent will be

(D) it estimates 73 percent of the nation’s 607 HMO’s would be profitable this year; last year that was only 36 percent

(E) only 36 percent of the nation’s 607 HMO’s last year were profitable, whereas they estimate it this year to be 73 percent

in D, the "it" hust follows the comma. in this, case it is not required, as the previous clause is already explaining the subject "interstudy". The misplaced "it" arises ambiguity and hence must be avoided.
Of the rest C is the best.
A, B and E have "they" which is plural and hence wrong.

Okay - I think I understand that it is unnecessary here, thus we should eliminate the choice D).

Thanks for your help.

D has redundancy. Remove the unnecessary part to make it easier to see.

D. According to Interstudy, it estimates 73 percent of the nation’s...

D has two methods of expressing the same thing. It can be better written as:
According to Interstudy, 73 percent of the nation’s...
or
Interstudy estimates that 73 percent of the nation’s...

Okay, that's very clear! Thanks for your help!

In the aforementioned sentence...

A,B and D all have misplaced modifiers. Between C and E, C sounds better

I will go with C, too