In which of the following states is the Gulf of Mannar Marine National Park…

A Marine National Park is a protected area notified under the Wildlife (Protection) Act, 1972 to conserve a marine or coastal ecosystem — coral reefs, seagrass meadows, mangroves, or estuarine habitats — found along a specific stretch of India's coastline. Because such habitats are geographically fixed to a particular shoreline, each marine park automatically falls within the jurisdiction of the coastal state or Union Territory whose coast it borders.

Applying this to the Gulf of Mannar

1. The Gulf of Mannar is the shallow sea between the southeastern tip of the Indian mainland and the northwestern coast of Sri Lanka, known for its coral reefs, seagrass beds, and pearl banks.

2. This stretch of coastline — from Rameswaram to Tuticorin (Thoothukudi) — lies entirely within Tamil Nadu.

3. The Gulf of Mannar Marine National Park was notified in 1986 over this coastline and today forms the core zone of the Gulf of Mannar Biosphere Reserve, India's first marine biosphere reserve.

4. Since the park's coastline belongs to Tamil Nadu, the park itself is administered as part of Tamil Nadu.

Ruling out the other states

• Gujarat — its marine park protects the Gulf of Kutch, a separate gulf on the western coast, not the Gulf of Mannar.

• Andaman Islands — protect the Mahatma Gandhi Marine National Park in the Andaman Sea, administered by the Union Territory, unconnected to the Gulf of Mannar.

• West Bengal — its major coastal reserve is the Sundarbans, a mangrove ecosystem on the Bay of Bengal delta, not a coral-reef marine park.

So among the offered states, only Tamil Nadu's coastline includes the Gulf of Mannar — confirming it as the answer.