We bought ( ) a piano, and ( ) liked it very much 填什麼,为什麼 A、them；they B、him；he答案是A

We bought ( ) a piano, and ( ) liked it very much 填什麼,为什麼 A、them；they B、him；he答案是A
We bought ( ) a piano, and ( ) liked it very much 填什麼,为什麼 A、them；they B、him；he
答案是A

We bought ( ) a piano, and ( ) liked it very much 填什麼,为什麼 A、them；they B、him；he答案是A
都可以,从语法上来说都是对的
如果硬是要选,第一看上下文,是给一个人买还是几个买,一个选B,几个选A
要是没有上下文,又硬要你选,从合理性来说,B更好,因为是一架钢琴,给他买了一架,比给他们买了一架更合理（一般思维定势是给他们应该买不止一架吧）
万恶的应试教育啊!

没有上下文的话，A，B都行。如果要说选最佳，就选B。