The correct option is D Ex situ conservation
Ex situ conservation refers to the conservation of a plant or an animal outside its natural environment. It is the more widespread and economically viable approach to the conservation of biodiversity. When it becomes difficult to conserve expanses of natural habitats like forests etc., sometimes for immediate rehabilitation, the animal is moved to Zoological Parks and rehabilitation centres. These are examples of ex situ conservation. Similarly, preserving seeds and gametes of endangered species is an instance of conservation wherein the environment or habitat of the species does not play a part.