Correct Option: A

Tusks are elongated, continuously growing front teeth, usually but not always in pairs, that protrude well beyond the mouth of certain mammal species. They are most commonly canines, as with warthogs, pig, and walruses, or, in the case of elephants, elongated incisors. The tusks are actually upper incisors, not canines. They are the only incisors the elephant has. Elephants, mastodons, and mammoths all have upper incisor teeth that emerge from the skull as tusks.