on the top of the mountain is an ancient tower dating back to hundreds of years ago .A. To

问题补充：

on the top of the mountain is an ancient tower dating back to hundreds of years ago .

A. To stand

B. Having stood

C. Standing

D. Stand

答案：

A. To stand

B. Having stood

(答案→)C. Standing

D. Stand

解析：地点状语位于句首，句子用完全倒装。故选C。