The correct answer is "1, 2, and 3" - all of the above-mentioned fauna of India are endangered.

1. Gharial: The gharial (Gavialis gangeticus) is a critically endangered crocodilian species found in the rivers of India. It is threatened by habitat loss, pollution, and poaching.

2. Leatherback turtle: The leatherback turtle (Dermochelys coriacea) is the largest marine turtle species and is listed as critically endangered. It faces threats from habitat degradation, pollution, fishing nets, and egg poaching.

3. Swamp deer: The swamp deer, also known as the barasingha (Rucervus duvaucelii), is a vulnerable deer species found in India. Its population has declined due to habitat loss and hunting.

All three species are recognized as endangered or vulnerable and require conservation efforts to protect their populations.