Question

Betty went to the museum and saw many pictures ________ were drawn by a famous person.

1. A.
   that
2. B.
   who
3. C.
   what
4. D.
   whom

Answer 1

A
定语从句缺主语时，先行词为人，用who/ that引导；先行词为物，用that/ which引导；缺宾语时，先行词为人，用whom引导从句（若关系代词前没有介词，也可用that/ who）；先行词为物，用which引导（若关系代词前没有介词时，也可用that）。句中的先行词pictures为物，因此选A。