Quote:
In reference to the ad placed in today's newspaper, several callers expressed interest in renting the currently empty loft.
A. In reference to the ad placed in today's newspaper, several callers expressed interest in
B. Referring to the ad placed in today's newspaper, callers expressed interest about
C. Referring to the ad placed in today's newspaper, callers have expressed interest in
D. With reference to the ad placed in today's newspaper, callers frequently expressed interest about
E. When referring to the ad placed in today's newspaper, callers frequently express interest about
MEANING: Referring to the ad placed today, callers have expressed interest in renting the currently empty loft.
NOTES: "referring" imps continuous action, and "have" is the present perfect, which describes an event that happened in the past and might continue in the present. Here callers are referring in the present to the ad placed in the past - hence, the present perfect is necessary.
Ans (C)