Which of the following is the SI unit of thermodynamic temperature?

The correct answer is option 3. Kelvin.

The SI unit of thermodynamic temperature is Kelvin.

The Kelvin (K) is the SI unit of thermodynamic temperature. It is defined based on the triple point of water, where the Kelvin scale starts from absolute zero (0 K), which is the lowest possible temperature where particles cease to move. This scale is widely used in scientific contexts, particularly in thermodynamics and physics, due to its direct relationship with the ideal gas law and other fundamental principles of thermodynamics.