It was ( ) we decided to go to the sea.

It was ( ) we decided to go to the sea.
A、such warm a day that
B、such a warm day as
C、so warm a day that
D、so warm a day as
【正确答案】：C
【题目解析】：so…that…如此…以至于，句子含义为天真热，我们打算去海边。