The building---- we live in is one of the most beautiful is

选D：
where是副词用作地点状语,相当于 in which place,当然place是泛指.
楼上的in which是错误的,自己都不懂别误人子弟拉.
这句话就相当于：The building where we live is one of the most beautiful is kunming.
building是名词不能作状语,必须加上介词如in才能作状语.