The correct option is (a) Edward Jenner.
Explanation:
Passive immunity was first discovered by Edward Jenner against chickenpox.
In passive immunity readymade antibodies (y-globulins) obtained from human or animal serum, who already had recovered from an infectious disease, are injected into human body to develop immunity.
It is used against measeles, rubella, mumps, diphtheria, tetanus, snake venom, scarlet fever, rabies and Salmonella and many other bacterial infection.
