What was Mansa Musa's primary objective when he brought Muslim architects and scholars to his cities after returning from Mecca?

To establish new trade routes with European kingdoms

To build military fortresses to defend against invaders

To transform his cities into major centers of Islamic learning and culture

To introduce new agricultural techniques to improve crop yields

Which action by Mansa Musa was most crucial in transforming Timbuktu from a trading post into a center of scholarship?

Lowering taxes on all goods traded in the city.

Building a large wall around the city for protection.

Recruiting Muslim architects and scholars after his hajj.

Moving his personal court and treasury to the city.