During the Second Half of the Fifteenth Century, the Incas

During the second half of the fifteenth century, the Incas:

A) Turned from conquest to consolidation.
B) Increased the scope of their military draft, using people who would otherwise have been left in their own villages.
C) Pulled back toward the administrative center to avoid the costs of constant warfare on the borderlands.
D) Faced foreign armies, often as well armed as the Incas, which led to a greater cohesion among the Incan elite aristocracy.