they stood on the top of the high building,_____ you could s

they stood on the top of the high building,_____ you could see the whole city.
A.from where
B.on where
C.from that
D.on it
但我觉得都不对,
我来说说自己的看法.
首先,定语从句中,that前不能有介词,所以我不会选C.
然后,我查阅了相关资料,from之后还可以跟介词短语,如:
The conductor heard sounds from behind him.
所以,该题相当于:
They stood on the top of the high building,from on the top of the high building you could see the whole city.
当然,我更倾向于:from the top of the building,即from which
我的意见是这样,)