Which Statement About the Mammal Fauna Native to North and South

Which statement about the mammal fauna native to North and South America is true?

A) There are some differences because the two continents were originally part of different "super continents."
B) They show some similarities because the Americas, distinct from Europe, Asia, and Africa, were once part of the same "super continent."
C) They show some similarities because the two continents split apart about 6 million years ago.
D) They show strong differences because the two continents were never connected.