Which of these would a paleontologist be most likely to do in order to determine whether a fossil represents a reptile or a mammal?

A)Look for the presence of milk-producing glands.
B)Look for the mammalian characteristics of a four-chambered heart and a diaphragm.
C)Because mammals are eutherians, look for evidence of a placenta.
D)Use molecular analysis to look for the protein keratin.
E)Examine the teeth.