The correct answer is option 'C' - Lord Wellesley.

Lord Wellesley, also known as Richard Wellesley, was the Governor-General of India during the Fourth Anglo-Mysore War. He served as the Governor-General from 1798 to 1805.

During his tenure, Lord Wellesley implemented several significant reforms and policies that greatly impacted British rule in India. He was known for his aggressive expansionist policies and his desire to establish British dominance in the Indian subcontinent.

Here is a detailed explanation of Lord Wellesley's role during the Fourth Anglo-Mysore War:

Overview of the Fourth Anglo-Mysore War:
The Fourth Anglo-Mysore War was fought between the British East India Company and the Kingdom of Mysore, ruled by Tipu Sultan. The war began in 1798 and concluded in 1799 with the defeat and death of Tipu Sultan.

Lord Wellesley's Objectives:
1. Eliminating the Threat: Lord Wellesley saw Tipu Sultan as a significant threat to British interests in South India. He aimed to eliminate Tipu Sultan's power and bring Mysore under British control.

2. Expanding British Influence: Lord Wellesley aimed to expand British influence and territories in India. He believed that controlling Mysore would provide strategic advantages and strengthen British control over the region.

3. Neutralizing French Influence: Lord Wellesley was also concerned about French support for Tipu Sultan. He aimed to counter French influence in India and prevent any collaboration between Tipu Sultan and the French.

Lord Wellesley's Strategies:
1. Formation of Alliances: Lord Wellesley formed alliances with neighboring rulers who were against Tipu Sultan's rule. He secured the support of the Marathas, the Nizam of Hyderabad, and the British-allied Travancore kingdom.

2. Military Campaign: Lord Wellesley launched a military campaign against Mysore to weaken Tipu Sultan's forces. The British East India Company's army, supported by the native allies, engaged in several battles against Mysore forces.

3. Siege of Seringapatam: The decisive battle of the war was the Siege of Seringapatam, the capital city of Mysore. The British forces, led by General Harris, successfully breached the city's defenses and captured it. Tipu Sultan was killed during the battle.

Outcome:
The Fourth Anglo-Mysore War ended with a decisive British victory. Mysore was divided, and the British took control of significant territories. The war marked the end of Tipu Sultan's rule and significantly weakened the power of the Kingdom of Mysore.

Conclusion:
Lord Wellesley played a crucial role as the Governor-General during the Fourth Anglo-Mysore War. His aggressive policies, military strategies, and alliances with neighboring rulers led to the defeat of Tipu Sultan and the expansion of British control in South India.