KAPLAN OFFICIAL EXPLANATION:

First of all, the subject for the underlined portion is a donation. Since the subject is singular, the pronouns that refer to it need to be singular as well. Eliminate (A) and (D) for using they and/or them rather than it. Compare (В), (C), and (E). Eliminate (E) because testing and to distribute are not parallel. Since both are in parallel situations, each describing what the blood banks need to do, they need to have the same structure. Finally, (C) is better than (B) because quickly testing it is more direct than testing it quickly and because before expiration at the end of (B) is less clear than before it expires. Go with (C).
_________________

+1 for C.

(A) by testing them quickly for a variety of illnesses and, before they expire, distributing them

(B) by testing it quickly for a variety of illness and distributing it before expiration

(C) by quickly testing it for a variety of illnesses and distributing it before it expires --> Correct, rectifies pronoun ambiguity and parallelism error

(D) by quickly testing it for a variety of illnesses and by, before they expire, distributing them

(E) by quickly testing it for a variety of illnesses and to distribute it before it expires

Hence, C.
_________________

Answer B - maintains correct parallelism - testing and distributing

But expiration of what exactly : blood bank/ hospital/ donated blood ?
I just found it redundant.
Please correct me if I am wrong.
_________________

'expiration' sounds bad, but i think expiration refers to it i.e. donation and pronoun error is not a deal breaker in Gmat.
But i may be wrong. Let's wait for some expert comments.

I think B is correct because there is a 'and' so testing has to be parallel with distributing.In option C there is a word quickly which is a modifier of testing.So I dont think quickly testing and distributing are parallel.

Posted from my mobile device

Expiration = Noun
Expire = Verb

Here we require a Verb thus "Expire" is needed, hope this helps !!!
_________________

This question is based on Pronouns and Parallelism.

Option A contains two ambiguous pronouns – them and they. These pronouns do not have a logical antecedent because plural pronouns cannot refer to the singular antecedent ‘a donation’. So, Option A can be eliminated.

Option B corrects the pronoun reference error committed in Option A. However, the adverb ‘quickly’ is misplaced. It should modify the participle ‘testing’ and so should be placed before it to avoid confusion. Furthermore, the phrase ‘before expiration’ is awkward and lacks clarity. So, Option B can be eliminated.

Option D is wordy. The phrase “by, before they expire’ is nonsensical. The preposition ‘by’ can precede a noun to convey a time by which an action should take place but it cannot precede a clause to convey the same meaning. So, Option D can be eliminated.

The sentence states that blood banks can make a donation useful by doing two things – testing and distributing. So, these two actions must be parallel in form. Option E lacks this parallelism, so it can be eliminated.

Option C maintains parallelism. This option also contains the appropriate pronoun reference. The singular pronoun ‘it’ can be used to refer to the singular antecedent ‘a donation’. Therefore, C is the most appropriate option.

Jayanthi Kumar.
_________________

Blood banks can only make a donation useful to a hospital by testing them quickly for a variety of illnesses and, before they expire, distributing them.


(A) by testing them quickly for a variety of illnesses and, before they expire, distributing them


Subject is "a donation", singular. Incorrectly using pronoun "them". Eliminated.


(B) by testing it quickly for a variety of illness and distributing it before expiration.

Using "it quickly" after the verb breaks the parallelism. If it does not break, it makes it less attractive a choice and can be kep alive with a heavy heart only to be eliminated after comparing with option C. Eliminated.

(C) by quickly testing it for a variety of illnesses and distributing it before it expires

Singular pronoun used. Perfectly parallel. Correct.

(D) by quickly testing it for a variety of illnesses and by, before they expire, distributing them

Subject is "a donation", singular. Incorrectly using pronoun "them". Eliminated.

(E) by quickly testing it for a variety of illnesses and to distribute it before it expires

By testing ....... and to distribute. Not parallel. Eliminated.

My answer is (C). It took me 01:34.

(A) No appropriate antecedent exists for "them / they" in "testing them" and "before they expire".
(B) Illness, as used to mean "a disease", is countable. “ a variety of illness” should be " a variety of illnesses".
(D) No appropriate antecedent exists for “they" in "before they expire".
(E) No parallelism between "by quickly testing it for a variety of illnesses" and "to distribute it before it expires".

imo C

Blood banks can only make a donation useful to a hospital by testing them quickly for a variety of illnesses and, before they expire, distributing them.
both the 'it' refers to a donation .

(A) by testing them quickly for a variety of illnesses and, before they expire, distributing them

(B) by testing it quickly for a variety of illness and distributing it before expiration

(C) by quickly testing it for a variety of illnesses and distributing it before it expires

(D) by quickly testing it for a variety of illnesses and by, before they expire, distributing them

(E) by quickly testing it for a variety of illnesses and to distribute it before it expires

Blood banks can only make a donation useful to a hospital by testing them quickly for a variety of illnesses and, before they expire, distributing them.


(A) by testing them quickly for a variety of illnesses and, before they expire, distributing them Incorrect

pronoun error - a donation singular, them plural

(B) by testing it quickly for a variety of illness and distributing it before expiration Incorrect

quickly for a variety of illness and expiration - both changes meaning and sound awkward

(C) by quickly testing it for a variety of illnesses and distributing it before it expires Correct

(D) by quickly testing it for a variety of illnesses and by, before they expire, distributing them Incorrect

same as A

(E) by quickly testing it for a variety of illnesses and to distribute it before it expires Incorrect

parallelism error - ........by quickly testing ...........and to distribute............

Blood banks can only make a donation useful to a hospital by testing them quickly for a variety of illnesses and, before they expire, distributing them.


(A) by testing them quickly for a variety of illnesses and, before they expire, distributing them
'them' has no antecedent

(B) by testing it quickly for a variety of illness and distributing it before expiration
'variety of illness' should be 'variety of illnesses'
'expiration' should be 'expiry'

(C) by quickly testing it for a variety of illnesses and distributing it before it expires
Correct

(D) by quickly testing it for a variety of illnesses and by, before they expire, distributing them
them has no antecedent

(E) by quickly testing it for a variety of illnesses and to distribute it before it expires
'testing' and 'to distribute' are not parallel.

Choice C is the answer.