Federal authorities involved in the investigation have found the local witnesses are difficult to locate, reticent, and are suspicious of strangers.

(A) the local witnesses are difficult to locate, reticent, and are
(B) local witnesses to be difficult to locate, reticent, and are
(C) that local witnesses are difficult to locate, reticent, and
(D) local witnesses are difficult to locate and reticent, and they are
(E) that local witnesses are difficult to locate and reticent, and they are

The underlined part of the sentence is a clause that must be introduced by the conjunction that. The witnesses are described in a series of three adjectives, or complements, each of which must be parallel; the witnesses are difficult to locate, reticent, and suspicious of strangers.

A That is omitted; the three elements in the series are not parallel
B The clause requires that, the three complements in the series are not parallel
C Correct. That introduces the clause in this sentence; the series of complements is parallel.
D That is incorrectly omitted; the three complements in the series are not parallel
E A parallel series should be x, y, and ; not x and y and they are z

The correct answer is C.

Join our Facebook Page for business school news, mba application tips, mba funding tips,GMAT tips and much more!