Sentence Correction

Unlike the modified salivary gland that injects venom through a snake tooth, Gila monsters' teeth rely on chewing and worrying prey to deliver a lethal dose.

A Gila monsters' teeth rely on
B a Gila monster tooth relies on
C that of Gila monsters rely on the
D that of a Gila monster's tooth relies on
E that of a Gila monster's is reliant on the

I think it's D