Explanation:

- Option 1: FG Hopkins was a renowned biochemist who discovered vitamins but had nothing to do with the development of the polio vaccine.

- Option 2: Jonas Salk developed the first successful polio vaccine in 1955. His work led to a dramatic reduction in polio cases.

- Option 3: Edward Jenner is famous for developing the smallpox vaccine in the late 18th century. He is often referred to as the pioneer of vaccination.

- Option 4: Robert Koch was a foundational figure in microbiology, known for discovering the bacteria responsible for tuberculosis and cholera.