Option 1: Hawksbill turtles

This option is incorrect. Operation Kachhapa is not focused on the conservation of Hawksbill turtles. Hawksbill turtles are a critically endangered species, but they are not specifically mentioned in the context of Operation Kachhapa.

Option 2: Olive Ridley sea turtles

This is the correct answer. Operation Kachhapa is an NGO initiative that focuses on the conservation of Olive Ridley sea turtles. The Olive Ridley turtle is a species of sea turtle found in the Indian Ocean and Pacific Ocean. It is listed as vulnerable on the IUCN Red List, and Operation Kachhapa aims to protect and conserve these turtles and their nesting sites.

Option 3: Green turtles

This option is incorrect. While Green turtles are also an important species in need of conservation, Operation Kachhapa does not specifically target Green turtles.

Option 4: Leatherback turtles

This option is incorrect. Operation Kachhapa does not focus on the conservation of Leatherback turtles. Although Leatherback turtles are critically endangered and in need of conservation efforts, they are not mentioned in relation to Operation Kachhapa.

Therefore, the correct answer is option 2, Olive Ridley sea turtles.