The correct answer is option 2: a surface-to-surface missile.

Prahaar is a missile developed by India and is classified as a short-range ballistic missile. It is designed to be launched from a mobile launcher, making it highly versatile and easily deployable in various terrains. The missile has a range of around 150 kilometers, which makes it suitable for engaging targets within a short to medium range.

It is important to note that the other options listed are incorrect. A battle tank (option 1) is a heavily armored and armed military vehicle designed for front-line combat. An aircraft carrier (option 3) is a large naval vessel used to deploy and recover aircraft and conduct operations in the sea. A submarine (option 4) is a watercraft that operates underwater and can carry out various missions such as reconnaissance, warfare, and missile launches.

Therefore, it is clear that option 2, a surface-to-surface missile, is the correct description of Prahaar.