The Invention of the Traction Plow in the Third Millennium

The invention of the traction plow in the third millennium B.C.E. was significant because it

A) enabled farmers to plough larger sections of land in a shorter amount of time.
B) enabled the children of farmers to pursue other trades, as fewer hands were needed on the farm.
C) led to a temporary decline in the world's population, due to its inefficiency.
D) encouraged city dwellers to take up farming as a reliable source of income.