I don't know___this answer is rightA.if Bwhere C.what D.how

I don't know___this answer is rightA.if Bwhere C.what D.how
I don't know___this answer is right
A.if Bwhere C.what D.how

I don't know___this answer is rightA.if Bwhere C.what D.how
if
表示 是否

if
是否

A.if-是否
意思:我不知道这个答案是否正确