Zamindars were a class of:

The correct answer is: a) Landowning aristocracy.

Zamindars were a class of hereditary landowners in India who held large tracts of land from the Mughal Empire. They were responsible for collecting taxes from the peasants who lived on their land and for maintaining law and order in their areas.

Option b) is incorrect because tenant farmers are peasants who rent land from landowners. Option c) is incorrect because merchants are people who buy and sell goods. Option d) is incorrect because religious leaders are people who lead religious groups.