One of the major contributors to our understanding of vaccination was Edward Jenner.
What is Jenner’s contribution to the development of vaccinations? Choose the statement that best describes the work of Edward Jenner.

a) He was the first person to demonstrate that it was possible to make a vaccine against a bacterial infection.
b) He discovered the process of passive immunization--the transfer of protective antibodies to an individual.
c) Jenner developed the process of variolation, whereby he infected people with ground smallpox scabs to protect them from smallpox.
d) He demonstrated that inoculating people with crusts from cowpox lesions protected them from smallpox infection.