Answer : 3. "Aircraft carrier "
Explanation :

INS Virat is a Centaur class aircraft carrier currently in service with the Indian Navy. INS Virat is the flagship of the Indian Navy the oldest carrier in service. Virat is currently the second largest ship in the Indian Navy after the INS Jyoti Viraat was completed and commissioned in 1959 as the Royal Navy’s HMS Hermes and was transferred to India in 1987.