Ex situ conservation literally means, "off-site conservation". It is the process of protecting an endangered species, variety or breed, of plant or animal outside its natural habitat; for example, by removing part of the population from a threatened habitat and placing it in a new location, which may be a wild area or within the care of humans.[1][2] The degree to which humans control or modify the natural dynamics of the managed population varies widely, and this may include alteration of living environments, reproductive patterns, access to resources, and protection from predation and mortality. Ex situ management can occur within or outside a species' natural geographic range. Individuals maintained ex situ exist outside an ecological niche. This means that they are not under the same selection pressures as wild populations, and they may undergo artificial selection if maintained ex situ for multiple generations.
The storage of seeds, pollen, tissue, or embryos in liquid nitrogen. This method can be used for virtually infinite storage of material without deterioration over a much greater time-period relative to all other methods of ex situ conservation. Cryopreservation is also used for the conservation of livestock genetics through Cryoconservation of animal genetic resources. Technical limitations prevent the cryopreservation of many species, but cryobiology is a field of active research, and many studies concerning plants are underway.
Somatic tissue can be stored in vitro for short periods of time. This is done in a light and temperature controlled environment that regulates the growth of cells. As a ex situ conservation technique tissue culture is primary used for clonal propagation of vegetative tissue or immature seeds. This allows for the proliferation of clonal plants from a relatively small amount of parent tissue.
The storage of seeds in a temperature and moisture controlled environment. This technique is used for taxa with orthodox seeds that tolerate desiccation. Seed bank facilities vary from sealed boxes to climate controlled walk-in freezers or vaults. Taxa with recalcitrant seeds that do not tolerate desiccation are typically not held in seed banks for extended periods of time.
Micropropagation is one of the ex situ techniques that has been used increasingly for the conservation of endangered plants. This in vitro technique aids in mass propagation of the plant species facing risk of extinction. The application of plant tissue culture techniques in orchid conservation and propagation requires an efficient in vitro regeneration protocol.
So the correct option is 'all are ex situ conservation methods'.