The correct option is A Vaccination
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Edward Jenner was an English doctor who introduced the vaccine for smallpox. In 1796, he inserted pus taken from Sarah Nelmes, a milkmaid with cowpox, into a cut made in the arm of a local boy, James Phipps. Several days later, Jenner exposed the boy to smallpox. He was found to be immune. Jenner called his new method ‘vaccination’ after the Latin word for cow (vacca).