The Stage Was Set for a Cataclysmic Shift in the Course

Multiple Choice

The stage was set for a cataclysmic shift in the course of history when  

A) Europeans increasingly demanded less expensive goods from Asia.
B) Africa was established as a source of slave labor.
C) the Portuguese demonstrated the feasibility of long-range ocean navigation.
D) the Renaissance nurtured a spirit of optimism and adventure.
E) All of these