you may have,you should gather your courage to face the chal

you may have,you should gather your courage to face the challenge.
A.However a serious problem B.What a serious problem
C.However serious a problem D.What serious a problem选C请解释一下however+形容词或副词+主谓的吗如however hot the weather is,she will not take off her coat.选项怎么分析啊谢谢