The correct option is D Botanical garden
In-situ conservation is on-site conservation or the conservation of genetic resources in natural populations of plant or animal species. It is the process of protecting an endangered plant or animal species in its natural habitat, either by protecting or cleaning up the habitat itself, or by defending the species from preadtors. Around 4% of the total geographical area of the country is used for in-situ conservation. The following methods are presently used for in-situ conservation is biosphere reserves, national parks and wild life sanctuaries. Botanical gardens are included under Ex-situ conservation.