India’s first indigenously built submarine was INS Vikrant. It was launched in 1967 and commissioned in 1971. It was a diesel-electric submarine and was decommissioned in 1997.
INS Delhi is a nuclear-powered attack submarine of the Arihant class. It was launched in 2014 and commissioned in 2016. It is the first nuclear-powered submarine to be built in India.
INS Shalki is a Kalvari-class diesel-electric attack submarine. It was launched in 2015 and commissioned in 2017. It is the first of six submarines of the Kalvari class to be built in India.
INS Savitri is a Shishumar-class diesel-electric attack submarine. It was launched in 1983 and commissioned in 1984. It is the third of four submarines of the Shishumar class to be built in India.
The correct answer is: A. INS Vikrant