this is NOT a GMATPREP verbal question. please don't post non-GMATPREP questions in the GMATPREP folder; thanks.
once the forum software allows, i will move the thread.
this problem comes from "1000sc", a source whose questions (and answers) are at best sketchy and at worst misleading. DO NOT USE 1000SC.
the only questions in that source with any redeeming value are problems that have been lifted from gmatprep. the others are almost entirely worthless rubbish.
there is NO WAY that an official problem would contain choices (d) AND (e), both of which would be considered correct. although one may claim that there is pronoun ambiguity in choice (e) - see
this post - there have been, and are, plenty of official problems containing a similar degree of "ambiguity" in their correct answers.