The key findings from many years of study of tiger population have indicated that in many sites, tigers decline in numbers because of habitat loss and prey depletion rather than being killed directly.
A tiger needs to eat about 50 deer-sized animals or 6,600 pounds of living prey every year. Wherever prey-base is adequate and good protection measures are in place tiger populations reach high numbers simply because the species breeds quickly.
Hence option C is the correct answer.