关于这个定语从句

问题描述:

关于这个定语从句
Music should be taught routinely in schools because of the benefits ______ can
have on the development of the brains of young children.
  A.which B.that C.it D.one
这个句子结构是怎么样的.如果是定语从句,那先行词是music的话,关系词在哪里,然后把music还原回从句应该放哪里?怎么会多了一个it呢?

C
本句不是定语从句,because of the benefits ______ can
have on the development of the brains of young children为原因状语从句.你可以讲得更具体一点么,这个原因状语从句的连接词呢?从句完整的句子是怎么样的呢很抱歉。我刚才错看了。本句是定语从句,it指代music.benefits 为先行词。本句可看成:because it(music)can have benefits on the development of the brains of young children.