Answer:
A. antitoxin used to treat exposure to a venom.
Explanation:
Antivenin is the antibodies created in the blood of animal when venom is injected in their body. It act as a neutralizer to the snake venom which entered in the body. In the human body, it can be used only once to treat snake bite as it may create allergic reaction in the human body. It was developed by Albert Calmette, a french Scientist.
Antivenin is an antitoxin used to treat exposure to a venom antigen produced from a virus.
