The correct answer is D. BHEL.
BHEL is a public sector undertaking that is associated with the erection and sometimes running of thermal power plants. It is a leading engineering, manufacturing, and construction company in India. It was founded in 1956 with the objective of developing and manufacturing heavy electrical equipment for the country’s power sector.
BHEL has a strong presence in the thermal power sector. It has executed a number of turnkey projects for the erection and commissioning of thermal power plants. It has also been involved in the operation and maintenance of thermal power plants.
BHEL is a well-respected company with a strong track record. It has a wide range of products and services that are used in the power sector, as well as in other sectors such as transportation, oil and gas, and defense.
The other options are incorrect.
NTPC is a public sector undertaking that is associated with the generation of electricity. It is the largest power company in India.
SAIL is a public sector undertaking that is associated with the production of steel.
BEL is a public sector undertaking that is associated with the production of electronics and defense equipment.