Explanation:

- Option 1: William Gilbert

- An English physician known for his pioneering work in magnetism and electricity.

- He did not make the first compound microscope.

- Option 2: Zacharias Janssen

- A Dutch spectacle maker credited with inventing the first compound microscope in the late 16th century.

- Often disputed but widely recognized for his contribution to microscopy.

- Option 3: John Harington

- Known for inventing the flush toilet during the Elizabethan era.

- Not related to microscopy.

- Option 4: Galileo Galilei

- An Italian astronomer known for his work in telescopic observations.

- Made significant contributions to science but not the first compound microscope.