The correct answer is option 4: a nuclear powered submarine.

To better understand each option:

Option 1: An infantry combat vehicle is a military vehicle designed for transporting infantry and providing fire support during combat. This option does not apply to the name "Arihant."

Option 2: A ballistic missile is a weapon that is launched into space and then travels along a ballistic trajectory to its target. This option does not apply to the name "Arihant."

Option 3: An attack helicopter is a type of military helicopter specifically designed and equipped for attacking enemy targets. This option does not apply to the name "Arihant."

Option 4: A nuclear powered submarine is a submarine that is powered by a nuclear reactor. These submarines have the ability to operate underwater for long periods of time without having to surface. The name "Arihant" has been given to one of the submarines of the Indian Navy, which is powered by a nuclear reactor. This is the correct option.

Therefore, the correct answer is option 4: a nuclear powered submarine.