Answer:
Correct answer is c . had a Golden Age & doubled in size.
Explanation:
Option A is not correct because Sundiata was the founder of the kingdom and ruled before Mansa Musa.
Option B is not correct as he ruled in the Late Middle Ages.
Option C is correct because during his reign Mali was the greatest exporter of gold, thus making Musa one of the richest rulers in the world. That is what helped country develop and even spread its boundaries.