The Northern Sultanates, Such as the Regime of Ala-Ud-Din of the Tughluqs

The northern sultanates, such as the regime of Ala-ud-din of the Tughluqs, supported their economies through __________.

A) Sponsoring extensive trade networks with Chinese traders.
B) Creating government-run and -operated kilns for porcelain production.
C) Heavy taxation, including the jizya tax on non-Muslims
D) Easing restrictions on the immigration of Hindus into their domains.