Sentence Correction

Why is C incorrect ?

Some patients who do not respond to therapies of depression may simply have received inadequate treatment, having, for example been prescribed a drug as a dosage too low to be effective or having been taken off a drug too soon.

A -- having, for example been prescribed a drug as a dosage too low to be effective or having been
B -- having, for example, a drug prescription that was ineffective because the dosage was too low, or being
C -- as, for example, having too low of a dosage of prescribed drug for it to be effective, or being
D -- when they have, for example, been prescribed too low a drug dosage for it to be effective, or were
E -- for example, when they have a drug prescription with a dosage too low to be effective, or been

IMO A...

first of all, this question seems tough and have a confusing structure...why?? because it contains certain words which we always ignore and here in this question we have to pick an answer choice which contains those certain words...i picked up Op A as an answer because i find correct parallelism in Op A and a correct use of Passive voice....

For Op C..."as, for example, having too low of a dosage of prescribed drug"...first the use of as indicates the comparison...noun of the first clause is PATIENTS....here, i believe having is modifying TREATMENT NOT PATIENTS...IN Choices A,B COMMA + HAVING is modifying patients but in Op C this is not the case...

Now flaw 1:-- AS comparison indicator and the comparison is made b/w patients and treatment

flaw 2:-- even if comparison if okay then if you break the 2nd clause considering treatment as the subject u get

"treatment having too low of a dosage of prescribed drug for it to be effective"---seems okay

and "treatment being off a drug too soon"---seems awkward and unclear...hence incorrect

i am between A and E
but at last E
i also like A for ||-ism, but i am slightly confused with having, for example been prescribed there is second comma after for example
and i don`t understand the usage: prescribed a drug as a dosage
to me it is ilogical to prescribe drug as a dosage.better to prescribe drug in a dosage

Are you sure this has been copied correctly? In the original "therapies of depression" is incorrect and should be "therapies for" or "therapies to treat". Also you prescribe a dosage of a drug, you don't prescribe a drug as a dosage.

Final solution at one place:

Important: The purpose of this post (and all the other posts by me) is to give a complete solution to all GMAT-Prep Verbal questions at one place. Sometimes students have to wade through dozens of posts to get to the final answer. My posts will give one complete and crisp solution required to arrive at the correct answer by eliminating the wrong ones. Some of the content in these posts may have been taken from various other sources (discussion forums).

Some patients who do not respond to therapies for depression may simply have received inadequate treatment, having, for example, been prescribed a drug at a dosage too low to be effective or having been taken off a drug too soon.
(A) having, for example, been prescribed a drug at a dosage too low to be effective or having been
(B) having, for example, a drug prescription that was ineffective because the dosage was too low, or being
(C) as, for example, having too low of a dosage of a prescribed drug for it to be effective, or being
(D) when they have, for example, been prescribed too low a drug dosage for it to be effective, or were
(E) for example, when they have a drug prescription with a dosage too low to be effective, or been

The best way to attack this problem is to remove 'for example' from each of the choices.

A. having been prescribed a drug at a dosage too low to be effective or having been
B. having a drug prescription that was ineffective because the dosage was too low, or being
C. as having too low of a dosage of a prescribed drug for it to be effective, or being
D. when they have been prescribed too low a drug dosage for it to be effective, or were
E. when they have a drug prescription with a dosage too low to be effective, or been

A is parallel 'having been || having been' ... the connector word is 'or' ... as we are joining two similar ideas (and only two ideas), we should not use a comma. This alone is sufficient to eliminate B, C, D, and E.

In B, 'having a drug prescription (refers to patients) can't be parallel to being taken off (refers to a doctor, possibly) ... as the subjects are different, the two are not parallel.

In C, 'having too low of a dosage (refers to patients) can't be parallel to being taken off (refers to a doctor, possibly) ... as the subjects are different, the two words are not parallel.

D is not parallel ('have been' is not parallel to 'were')

E is not parallel ('have a prescription' is not parallel to 'been taken off')

Correct: A

I ruled out A as:
I thought since the sentence is giving two examples 'having been prescribed ..' and 'having been taken off...' both should follow after 'for example'. So it should look like - "for example, having been prescribed a drug as a dosage too low to be effective or having been"

How can I make myself familiar with this kind of structure.

Is E incorrect because -
'have a drug prescription (simple present/active)' and 'have been taken off (present perfect/passive) are not parallel. Which one is a bigger deal tense or voice change?

Is this an official problem?

Experts pls help