Explanation:

- Wind turbines convert kinetic energy into mechanical power.

- ?? Option 4: Kinetic energy is the energy of motion; wind's movement turns the blades.

- This is the direct form of energy conversion in wind turbines.

- Option 1: Chemical energy involves energy stored in bonds of chemical compounds.

- Wind turbines don't deal with chemical reactions.

- Option 2: Nuclear energy comes from atomic nuclei.

- It has no role in the functioning of wind turbines.

- Option 3: Gravitational energy is related to the potential energy due to gravity.

- Not a part of wind energy conversion.