Answer:
Correct answer is c. made advances in science, mathematics, and medicine.
Step-by-step explanation:
A is not correct as Confucius was influential in China, not in Abbasid Empire.
B is not correct as the Germanic tribes didn't exist back then. They created their states after the fall of Western Roman Empire.
C is correct as the development in natural sciences in this period affected everyone at the time, even people in Europe.
D is not correct as Islam was official religion.