The headmaster asked me to_____ him at his office.

The headmaster asked me to_____ him at his office.
A、drop in
B、call in
C、drop in on
D、call on in
【正确答案】：C
【题目解析】：drop in 落进；call in 召集；drop in on 顺道拜访；call on in 错误搭配，call in on 才是顺道拜访的意思；句意：校长让我到他的办公室去拜访他。因此C符合题意