The weather in Beijing is much better than ( )选择

问题描述:

The weather in Beijing is much better than ( )选择
A.that used to be
B.it used to be
C.that used to
D/it used to
为什么不是A

B
北京的天气比以前好多了.
used to be 意思是:过去是;曾经怎样.