I don’t think he’s so great,but my mom _________.A.do B.does C.is D.are选哪个为什么

I don’t think he’s so great,but my mom _________.A.do B.does C.is D.are
选哪个为什么

B does
这个句子完整是my om thinks he is so great
避免thinks的重复,用does代替