(A) Galileo Galilei
(B) Marie Curie
(C) Edward Jenner
(D) None of these
🧠 Explanation:
The discovery of the vaccine is credited to **Edward Jenner** in 1796.
He observed that milkmaids who had contracted cowpox, a mild disease, seemed immune to smallpox, a deadly illness at the time. Jenner tested this by introducing material from cowpox sores into a young boy’s arm and later exposing him to smallpox. The boy did not develop the disease, proving the protective effect. This experiment laid the groundwork for immunology and the development of future vaccines. Jenner’s work marked a turning point in medical history, leading to the eventual eradication of smallpox and inspiring research into vaccines for many other diseases.
