高中英语语法选择题From the top of the tower( )

高中英语语法选择题From the top of the tower( )
From the top of the tower( )
A.could the whole city be seen
B.could see the whole city
C.could be seen the whole city
D.could be the whole city seen
选C,这是全倒是吧,不知道这种又是情态动词,又是全倒,又是被动,
可以的话,帮忙总结下要全倒的情况吧,