请教各位关于此题
The increase in profits during the third quarter was ___
due to a national advertising campaign.
A.almost
B.most
C.mostly
正确答案为C,但为何不是B 或A呢?
谢谢~!

我觉得是考词意没错欸 毕竟due是形容词而三个选项都是副词这样