The Subsidiary Alliance, under which Indian rulers kept British troops at their own cost, was introduced by

Explanation

1. 01

   Lord Wellesley, Governor-General from 1798, used the Subsidiary Alliance to bring Indian states under Company control without war.

2. 02

   A ruler who signed kept a British force, paid for it, and could not make treaties with others without the Company's consent. Hyderabad was the first to accept, in 1798.

3. 03

   Dalhousie's instrument was the Doctrine of Lapse, a different policy fifty years later.