One of the Major Reasons for the Growth of the World

One of the major reasons for the growth of the world population after 1700 was

A) recovery from the plague.
B) large-scale development of the plantation economy in the new world and the growth of staple crops.
C) the spread of more high-calorie per acre staple crops like maize and potatoes from the New World.
D) the transition to a mercantile, cash-based economy.
E) exposure of the different populations to each other strengthened the global immune system.