As Humans Evolved, Our Teeth and Jaws Got Smaller Because

As humans evolved, our teeth and jaws got smaller because:

A) people with small teeth and jaws were less likely to die off once we figured out how to cook and prepare foods that were easier to chew.
B) we no longer needed to chew sinews and leather and branches to make tools.
C) those who could speak more clearly (i.e., who were not impeded by large teeth and jaws) had higher fertility and lower mortality.
D) when we began to cook, those with protruding jaws often burned their faces in the fire, couldn't eat, and died off.
E) small jaws and teeth provided a selective advantage.