单项选择题

The author provides information that would answer which of the following questions’ Ⅰ. What eventually led to the extinction of the robust proto-humans Ⅱ. What were the causes of the desiccation of the African landscape Ⅲ. What caused the initial spurt in Homo’s brain growth

A. Ⅰ only
B. Ⅲ only
C. Ⅰ and Ⅱ only
D. Ⅱ and Ⅲ only
E. Ⅰ, Ⅱ, and Ⅲ