Sentence Correction

Organic vegetables are free of chemicals and healthier than regular agricultural produce is.


a) healthier than regular agricultural produce is
b) more healthy than regular agricultural produce is
c) healthier as regular agricultural produce is
d) healthier than regular agricultural produce
e) are as healthy than regular agricultural produce is

OA is a.However, need to know why option "d" is incorrect.

ELLIPSIS is the omission of words whose presence is understood.

Generally, a verb form that is omitted should appear earlier in the sentence.
For the purpose of ellipsis, the singular and plural versions of the basic form of a verb -- runs and run, sings and sing, generates and generate -- are considered the same verb form.
Mary runs faster than her sisters.
Implied comparison:
Mary runs faster than her sisters [run].
The verb in brackets is omitted, but its presence is implied.
Since runs and run are considered the same verb form, this ellipsis is correct.

Sagar Joshi wrote:need to know why option "d" is incorrect.

D: Organic vegetables are healthier than regular agricultural produce.
There is no error here.
Implied comparison:
Organic vegetables are healthier than regular agricultural produce [is healthy].
The words in brackets are omitted, but their presence is understood.

I would ignore this SC.

Thanks a lot !