英语语法选择题求大神解答

Question

Air is a mixture（）components are very useful in the chemical industry
AwhichBwhoseCthatDits为什么是选B呢

Answer 1

Air is a mixture（）components are very useful in the chemical industry AwhichBwhoseCthatDits为什么是选B呢
因为它和先行词之间是所有格的关系。

追问

可以解析清楚点吗 谢谢

追答

名词所有格