The correct option is C Botanical garden
Ex situ biodiversity conservation
Ex situ (off site) conservation is the approach of conserving species by taking them out from their natural habitats and then keeping them in a special setup under human care.
Botanical gardens
A botanical garden is a garden where plants are grown for their collection, preservation, and scientific study. This method of conservation comes under the ex situ approach of conservation.
Biosphere reserves
Biosphere reserves include terrestrial, marine and coastal ecosystems that are nominated by the national government but remain under the jurisdiction of the state where they are located. This belongs to the in situ approach of conservation where the species is conserved in its natural habitat.
National parks
National parks are the areas that serve the purpose of conservation of biodiversity present in that particular area and are protected by the government. This belongs to the in situ approach of conservation where the species is conserved in its natural habitat.
Reserve forest
Reserve forests are the forest areas that are protected by the government and local people are prohibited from entering there. This is an in situ conservation approach.