it's the most beautiful mountain that i have never seen.这句话对吗?

问题描述:

it's the most beautiful mountain that i have never seen.这句话对吗?
请问下面这道题选什么:
it's _______ moutain i have never seen.
a.a beautiful b the most beautiful c.a more beautiful

B
这是我见过的最漂亮的山脉了.