Which one of the following Central Public Sector Enterprises is a "Navratna"?

Option 1 -> Indian Oil Corporation Limited is a Maharatna company (higher status than Navratna), not a Navratna.

Option 2 -> Steel Authority of India Limited is also a Maharatna company, not a Navratna.

Option 3 -> Central Coalfields Limited is a Miniratna Category-I company (lower status than Navratna).

Option 4 -> Mahanagar Telephone Nigam Limited is a Navratna company, granted this status in 1998.

Hence, Mahanagar Telephone Nigam Limited -> MTNL is the only company among the options that holds Navratna status. The other three companies hold either higher status (Maharatna for IOCL and SAIL) or lower status (Miniratna for CCL) in the Government of India's PSE categorization system -> correct