The correct answer is uneven heating of Earth's surface.
Wind is a result of uneven heating of the surface of the Earth by the Sun. As the surface of the Earth is formed of different kinds of water and land, it absorbs the heat of the Sun at different intensities. One illustration of this uneven heating is the daily wind cycle.
This uneven heating results in modifications of atmospheric pressure and the wind start to blow from the regions with high pressure to the regions with low pressure.