最好用as.
这个句子显然想考察【as引导非限制性定语从句】的用法.
单就一般用法而言,这里用which也行.
不过,as用法中,除了意思不同于which之外,还有一些经常搭配动词和固定结构,其中最好不要变更用词：
as sb expect/know/believe/suppose/think/consider/regard/suggest/recommend/advise,
as is expected/known/believed/supposed/thought/suggested/recommended/advised,
as is often the case, such...as...;the same...as...等.
因此,结合as的习惯用法,这句话中最好用as.
祝你开心如意!