With reference to the economic history of medieval India, the term 'Araghatta' refers to
Explanation
The term 'Araghatta' refers to a waterwheel used to lift water from wells for irrigation, a technological innovation that significantly boosted agricultural productivity in medieval India. While land grants to military officers (Option b) were a central economic feature, they were referred to as *Iqta* or *Jagir* rather than Araghatta. This question tests the core concept of technological advancements and mechanical devices used in the medieval Indian agrarian economy.