答案A.some of which
The medicine has many functions,(some of which) are unknown to us.
翻译：药有许多功能,鞭中一些我们尚未得而知.
改写
The medicine has many functions.Some of the functions are unknown to us.
some of which引导的是一个定语从句,修饰前面的functions
其他几个无论从语法还是意思上都不合理