He's a very dangerous guy, which is why I lied to the police officer.中文意思？which is 什么词性？

Question

如题所述

Answer 1

他是很危险的家伙，这就是我和警察撒谎的原因。。
which is 是定语从句的开头。

Answer 2

他是一个非常危险的家伙，这也就是为什么我对警员撒谎。
which is是同位语吧

Answer 3

which连接代词。不过这里好像应该用that
is系动词
He's a very dangerous guy, that is why I lied to the police officer.他是很危险的家伙，这就是我对警官撒谎的原因。