The correct answer is option 2: thermal power. Thermal power generation refers to the process of converting heat energy into electrical energy. In India, thermal power accounts for the largest share of power generation. This is because India has abundant coal reserves, which are used as fuel to generate electricity in thermal power plants. These power plants use steam generated from burning coal to drive turbines and generate electricity. Thermal power plants are widely distributed across the country and are capable of producing large amounts of electricity. Other sources of power generation, such as hydro-electricity, nuclear, and solar, also contribute to India`s power generation, but thermal power currently occupies the largest share.