only those__knows well could be let in .A did he B who C whom he D he did.为何选C

only those__knows well could be let in .A did he B who C whom he D he did.为何选C
only those__knows well could be let in .
A did he B who C whom he D he did.
为何选C

only those__knows well could be let in .A did he B who C whom he D he did.为何选C
a 的话knows不能加s
b的话没有先行词
d的话knows改为know

c