Edward Jenner Promoted the Use of Cowpox Infection,that Was Very

Edward Jenner promoted the use of cowpox infection,that was very similar to more dangerous smallpox,as a vaccination to provide patients immunity from future smallpox epidemics.This was a case of these subjects

A) developing passive immunity.
B) developing active immunity.
C) developing an inflammatory response that increased the IgG production.
D) developing high levels of complement.
E) developing high levels of interferon although Jenner did not realize these diseases were viral.