Hint: The wild Buffalo (Bubalus arnee) is an animal belonging to the Bovine group is also known as Asian Buffalo or Asiatic Buffalo. It is native to the Indian subcontinent as well as in Southeast Asia.
Endangered species are those which are on the verge of extinction. And the existing species face the risk of extinction. The population of these animals is on a decline since the final three generations, and the studies have found the possibility of the rates to get projected to the future. The decline in the population is due to the loss of its habitat as well as climatic change. Thus they are considered as endangered species.
Considering the other given options:
-The species whose populations have gone extinct from the earth are known as Extinct species. The extinction can be either due to overexploitation or even due to evolutionary processes. An example of a species that got extinct is the Baiji River Dolphin present in China. Thus it is not an appropriate option.
-It is not the correct option since the species which are found only in a particular geographic area are known as endemic species. An example of endemic species is the Lemur of Madagascar.
-The process of illegally hunting or capturing wild animals is known as poaching. It is enforced to prevent these species from getting extinct. Thus it is not an appropriate option.
Thus, the most appropriate one among the given options is A that is, wild buffalo is an endangered species because its population is diminishing.
Note: Poaching disrupts the balance in an ecosystem and threatens the existence of many animals. Due to excessive poaching, some of the organisms get extinct over time. Thus the process should be legally controlled or stopped.