Mercury thermometer was invented by:

The mercury thermometer, a crucial instrument for measuring temperature, was invented by Daniel Gabriel Fahrenheit. In 1714, Fahrenheit developed the first reliable mercury-in-glass thermometer and also introduced the Fahrenheit temperature scale, which is still used in some regions today. His innovations significantly advanced the field of thermometry.

• Galileo Galilei is credited with inventing an early form of thermometer, the thermoscope, around 1593, but it was not a mercury thermometer.
• Isaac Newton made profound contributions to physics and mathematics, but he did not invent the mercury thermometer. He did propose a temperature scale, but it was not widely adopted.
• 'None of these' is incorrect because Fahrenheit is the correct inventor.