In the Late 1800s,a Frenchman Observed That Individuals Who Recovered

In the late 1800s,a Frenchman observed that individuals who recovered from a disease were not susceptible to that same disease again.Therefore,he proposed that the agent that caused syphilis should be given to all young healthy people as a vaccine to prevent them from getting a serious case of the disease.Although the mode of action of vaccines was not yet known,Pasteur argued vehemently against this proposal.And today,we do not follow this procedure for syphilis.Why?

A) Vaccines only work against a few pathogens.
B) Vaccines do not work for pathogens that are vulnerable to antibiotics.
C) Syphilis is an autoimmune disease.
D) It might work, but Pasteur was a famous authority and his ideas prevail today.
E) Vaccines are made from weakened disease agents and using the syphilis organisms would spread a full-blown serious disease agent.