museum is one of the most famous museums____ open to the publicA that are B that is为什么选B,为什么是IS?还有,这句是什么从句?

问题描述:

museum is one of the most famous museums____ open to the public
A that are B that is
为什么选B,为什么是IS?还有,这句是什么从句?

定语从句 先行词是one不是museums