Question

this man discovered the first vaccination when he observed that milkmaids who are exposed to cowpox do not get smallpox. joseph lister. edward jenner hippocrates galen

Explanation:

Edward Jenner is known for discovering the first vaccination. He noted that milkmaids exposed to cowpox were immune to smallpox and developed the small - pox vaccine based on this observation.

Answer:

B. Edward Jenner