请教一道英语填空题：My parents_________ of that schoo1.A.both are teac

请教一道英语填空题：My parents_________ of that schoo1.A.both are teachers B.are both teachers C.
My parents_________ of that schoo1.A.both are teachers B.are both teachers C.are teachers both D.both teachers are
请问答案为什么是B

oth 是限定词 对名词起限定作用 因此要放在名词之前