Answer & Explanation
C) Lord Wellesley
The doctrine of the subsidiary alliance was introduced by Lord Wellesley, British Governor-General of India from 1798 to 1805.
The Nizam of Hyderabad was the first to enter into such an alliance in 1798. Tipu Sultan of Mysore refused to do so, but after the British victory in the Fourth Anglo-Mysore War, Mysore was forced to become a subsidiary state in 1799.
The Nawab of Awadh was the next to accept the Subsidiary Alliance, in 1801.