How did the inca empire's policy of mandatory public service contribute to development of its empire? a) it allowed them to outlaw slavery. b) it made mandatory education unnecessary. c) it made the construction of roads possible. d) it to avoid using heavy taxation.

D) It helped to avoid using heavy taxation.

Explanation:

Since the  Inca empire had mandatory public service, this was free labor, this meant that they didn´t have to pay for the work that people were doing this meant that they didn´t have to tax more to pay for those workers, so people weren´t actually taxed buy they helped the empire working for free and building and maintaining what have to be built. The culture of community also helped a lot for people not to feel like it was a mandatory, they saw it as a way to contribute to the society and the community.

b. by enlisting in the military to fight