This tower they are planning to have decorated is always the best place to have a view o

问题补充：

This tower, they are planning to have decorated, is always the best place to have a view of the sea.

A. where

B. what

C. which

D. that

答案：

A. where

B. what

(答案→)C. which

D. that

解析：句意：他们计划装修的一座塔是看海的好地方。这里是非限制性定语从句，先行词是tower，关系词在从句中作宾语，故排除A，what不能引导定语从句，that不能引导非限制性定语从句，故选C。