Sea Vigil is described as a build-up to which larger exercise of the Indian Navy?

The correct answer is TROPEX, the Theatre Level Readiness Operational Exercise, which the Indian Navy conducts once in two years. Sea Vigil is treated as a build-up to it, and the two exercises read together address the entire spectrum of maritime security challenges, from the defence of the coast to operations far out on the high seas. Options B, C and D name exercises that are not described in this connection. MILAN is a multinational gathering of navies, Varuna is conducted with the French Navy and Malabar is held with partner navies including the United States and Japan, but the release links Sea Vigil specifically to TROPEX. Remember the division of labour being tested here: Sea Vigil assesses the nation’s preparedness for maritime security and coastal defence at the apex level, covering the whole coastline and the Exclusive Economic Zone, with the Coastal Defence and Security Readiness Evaluation phase preceding the Sea Phase.