For PLATO:
Maya: Created hieroglyphic writing system
Developed the accurate calendar systems
Constructed Chichen Itza
Aztec: Built Tenochtitlan
Sustained 20mil population
Grew floating gardens
I would pick C but wait for more answers
Answer:
push: political and religious persecution
pull: open immigration policies
push: overpopulation
pull: moneymaking opportunities
push: lack of economic opportunities
pull: the "American Dream"
Explanation: