The correct answer is INS Mahe. INS Mahe is the lead ship of a class of Anti-Submarine Warfare Shallow Water Craft (ASW-SWC) built for the Indian Navy. Vessels of this class are designed to detect and hunt submarines in coastal, shallow waters and to conduct subsurface surveillance, low-intensity maritime operations, and mine-laying close to the coast. Commissioning such a ship in November 2025 directly strengthens India's anti-submarine and coastal defence capabilities, which is exactly what the question describes.

The other options are real Indian Navy vessels but do not match this role or timing:

• INS Vikrant is India's first indigenously built aircraft carrier, commissioned in 2022 — a large power-projection platform, not a coastal anti-submarine craft.
• INS Arnala is also an anti-submarine shallow-water craft of the same broad programme, but it is a separate ship and does not fit the specified November 2025 commissioning.
• INS Ikshak is a survey (hydrographic) vessel whose job is charting the seabed and waters, not hunting submarines.

Because only INS Mahe combines the anti-submarine, shallow-water, coastal-defence purpose with the stated commissioning, it is the right choice.