The term "Blue Revolution" is related to option 3, fishing. The Blue Revolution refers to the transformation and modernization of the fishing industry. It involves the adoption of advanced techniques and technologies in fishing practices, such as the use of large fishing vessels, improved processing techniques, and the cultivation of fish in controlled environments like fish farms. This revolution aims to increase the production and productivity of fish and seafood, meet the growing demand for seafood, and improve the economic conditions of fishing communities. Irrigation, option 1, is not directly related to the Blue Revolution, as it mainly pertains to the supply of water to agricultural fields. Agriculture, option 2, is a broad term that includes various activities related to cultivating crops and rearing livestock, but it is not specifically related to the Blue Revolution. Option 4, indigo cultivation, is not related to the Blue Revolution at all.