In situ conservation is the production and management of important components of biological diversity through a network of protected areas. This can be wildlife sanctuaries, national parks, biosphere reserves etc.
Ex situ conservation is the conservation of selected rare plants or animals in places outside the natural forms.
Ex-situ conservation includes off-site collection and gene banks. Ex situ conservation is conserving the animals and plant outside the natural habitat.
Ex situ conservation includes offsite collection and gene banks.
Offsite collections are the live collection of file and domesticated species in the botanical garden.
Gene bank is an institution where available plant material is preserved in a viable condition.
Seed Bank stores seed in viable state Cryopreservation is preserving things in liquid nitrogen.
Zoos or zoological parks are places where animals are kept in captivity and bred.
So, the correct option is 'Cryopreservation'