In-situ conservation is the protection and management of important components of biological diversity through a network of protected areas, e.g., national park, biosphere reserve, sanctuary etc.
Ex-situ conservation is the conservation of selected rare plants/ animals in places outside their natural homes. Ex-situ conservation includes offsite collections and gene banks. The two are also a source of genetic material for breeders and genetic engineers. The offsite collection is live collections of wild and domesticated species in botanical gardens, zoos, arboreta etc.
Hence, from the given options, a botanical garden is the one that doesn't fall under in situ conservation.