Answer:
Option: A. Each region had resources that other regions did not, so they began to depend on one another.
Explanation:
In the New Kingdom, trade extensively spread from region to region. Egypt traded grain to the Roman Empire and became breadbasket. The lack of other resources like metal, wood, and other precious stones led them to rely on other regions for trade. Gold sent from Nubia. The New Kingdom craved for luxury items and introduced to it in various forms as there was direct contact with other regions than earlier during the Old Kingdom.
Over expansion weakened Rome because the military couldn't protect that much land from foreign invaders.