Correct answer: A. Bengal
Explanation: The Indigo Revolt was a peasant movement against the forced cultivation and unfair treatment connected with indigo production under colonial rule. Indigo planters pressured cultivators to grow indigo on land that could otherwise be used for food crops. Peasants objected to coercive contracts, low returns, and the burden placed on them. The movement became a major example of rural resistance in nineteenth-century India.
The revolt began and spread mainly in Bengal, especially among peasants in areas where European indigo planters operated. Therefore choice A, Bengal, is correct. Punjab, Kerala, and Rajasthan were important regions in other historical contexts, but they are not the principal region associated with the Indigo Revolt. Remembering the pairing of indigo cultivation, peasant resistance, and Bengal helps identify the answer without confusing it with other regional movements.