The vaccine for smallpox was discovered by Edward Jenner, making Option 3 the correct answer. Here is a detailed explanation supporting this: 1. Edward Jenner (Option 3): Edward Jenner, an English physician, is credited with the discovery of the smallpox vaccine in 1796. He observed that milkmaids who had contracted cowpox, a disease similar to smallpox but much milder, did not catch smallpox. Jenner hypothesized that exposure to cowpox could…Read More