The correct answer is (d) All of the above.
SAIL, GAIL, and MTNL are all public sector undertakings that are included in the ‘Navratna’ list.
A Navratna is a public sector undertaking (PSU) in India that has been designated as a “jewel of the crown” by the government. Navratnas are given greater autonomy and flexibility than other PSUs, and they are expected to be more competitive in the global marketplace.
SAIL is the Steel Authority of India Limited, and it is the largest steel producer in India. GAIL is the Gas Authority of India Limited, and it is the largest natural gas company in India. MTNL is the Mahanagar Telephone Nigam Limited, and it is a telecommunications company that provides services in the Delhi and Mumbai metropolitan areas.
All three of these companies are important contributors to the Indian economy, and they are all playing a role in the country’s development.