Charles Darwin Noted That the Human Lineage Probably Arose Out

Charles Darwin noted that the human lineage probably arose out of Africa. Which of the following was MOST likely the reason behind his hypothesis?

A) Africa has warmer temperatures, which allows for greater diversity.
B) Gorillas and chimpanzees, which are the primates most closely related to humans, only live in Africa.
C) Africa was the first land mass that was suitable for life.
D) This was before the advent of molecular analysis, so Charles Darwin was incorrect.
E) None of the answer options is correct.