Answer : 4. "Patrol Ship"
Explanation :

Recently, Indian Navy's Saryu-class patrol ship INS Sumitra rescued kidnapped fishermen off the eastern coast of Somalia. Commissioned in 2014, it is the last ship of its class built by Goa Shipyard. Based at Chennai under the Eastern Naval Command, its primary roles include EEZ surveillance, anti-piracy patrol, fleet support, maritime security and escort operations. Recent successful rescues underline its important contribution to regional security.