Arihant is a
- Multi barrel rocket launcher
- Airborne Early Warning and Control System
- Unmanned Combat Aerial Vehicle
- Nuclear-powered ballistic missile submarine
The Arihant class is a class of nuclear-powered ballistic missile submarines being built for the Indian Navy. The lead vessel of the class, INS Arihant, was first launched in 2009 and began sea trials in December 2014.
The correct option is D.