The image below shows a certain type of global wind: (3 points)

The Earth is shown as a circle. Equator is shown and labeled at 0 degrees. 30 degrees north and south latitudes are shown and labeled. 60 degrees north and south latitudes are shown and labeled. Curved arrows are shown pointing from 30 degrees north and south latitudes towards the equator.

What best describes these winds?
Polar easterlies caused by air above poles being relatively warmer
Polar easterlies caused by air above poles being relatively cooler
Trade winds caused by air above equator being relatively warmer
Trade winds caused by air above equator being relatively cooler