Answer:
The correct answer is a. artificial passive immunity
Step-by-step explanation:
Antiserum is produced by injecting snake venom to animals like horses and the antibodies produced by this exposure in horses are taken out and used as antiserum.
Passive immunity is the immunity in which the antibody is given from outside and this antibody protects the particular person against a particular antigen. Passive immunity can be natural or artificial.
So here the antigen is snake venom protein and antibody is antiserum which is artificially produced and provide passive immunity to the person who had snake bite.
Therefore, the correct answer is a. artificial passive immunity.