[求助]用作引导定语从句，that 和which有什么区别？？

弱问一下

1）用作引导从句，that 和which有什么区别？

OG11  7

Carnivorous mammaals can endure what would otherwise be lethal levels of body heat because they have a heat-exchange network which kept the brain from getting too hot.

A  which kept

B that keeps

C which has kept

D that has been keeping

E having kept

这题答案是B，没有疑问

但是og上关于which和that的区别不明白？

The pronoun which intrduces nonrestrictive clauses,which include information relevant but not critical to an understanding of the sentence.

The pronoun that intrduces a restrictive clauses,which is critical to an understanding  the sentence beause the clause defines its antecedent.

Here,the clause following which defines beat-exchange network,so that must be used in place of which.

which 用作引导定语从句，只能跟非限定性定语从句？而that 用作引导定语从句，只能跟限定性定语从句？

我很疑惑！

好心人帮忙解释一下好吗？