OG11 SC#7

请问，如果OG 11 SC #7（如下）有这样一个选项“, which keeps”是不是也是错误的。no, it's correct but that keeps is better.  因为这里必须要一个限制型定语从句来解释heat-exchange network不然理由就不够strong了？i don't think so.
            

The sentence without 定语从句-Carnivorous mammals can endure what would otherwise be lethal levels of body heat because they have a heat-exchange network -
                    is still correct.

Carnivorous mammals 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

谢谢