Answer:
Correct answer is C. It was home to the Great Mosque.
Step-by-step explanation:
It was home to the Great Mosque, because on the place where we today have a modern mosque we had a medieval mosque that was built in 13th or 14th Century.
A is not correct because there were many trading centers in that period, and as you can see Islam spread there a bit later.
B is not correct as it is site of UNESCO since 1988.
D is not correct as it was never his capital.