If you do care for which or that, then be sure about these simple rules. 1. Which can never be used without a comma before it and that is never used with a comma before it. Thus A and B are out. D is a fragment without a working verb for the sub-clause. E is also a fragment in this portion - employers who offer benefits such that employees are permitted a balance between home and work responsibilities – There is no verb to represent the action of the employers who offer benefits.
C, therefore, is the choice.
However, it is worthwhile to note GMAT’s thinking on this issue from the following topic.- (
OG 12 SC Q 10)
Carnivorous mammals can endure what would
otherwise be lethal levels of body heat because they
have a heat-exchange network which kept the brain
from getting too hot.
(A) which kept
(B) that keeps
(C) which has kept
(D) that has been keeping
(E) having kept
Official explanation
Verb form; Rhetorical construction
Th e use of the past tense (kept) is incorrect
because a current situation is discussed; the
present tense (keeps) is consistent with the other
verbs in the sentence. In (A) and (C), which
introduces a restrictive clause. Some writers
follow the convention that which can only be used
for nonrestrictive clauses, but insistence on this
rule is controversial, and both (A) and (C) can be
rejected on other grounds
I do not think GMAT is fussy about the use of which or that and therefore look for other grounds in the sentences than getting stuck.