The Westerlies are global prevailing winds that blow from the west to the east in middle latitudes, typically between 30 and 60 degrees latitude. They are named so because they blow from the west. Understanding the origin of the Westerlies can help in understanding their direction and behavior.

Option 1: Polar highs

Polar highs are areas of high atmospheric pressure near the poles. However, the Westerlies do not originate from the polar highs.

Option 3: Equatorial lows

Equatorial lows are areas of low atmospheric pressure near the equator. The Westerlies do not originate from equatorial lows.

Option 4: Sub polar lows

Sub polar lows are areas of low atmospheric pressure located in the high latitudes but just below the polar region. The Westerlies are actually influenced by these sub polar lows, but they do not directly originate from them.

Option 2: Subtropical highs

Subtropical highs are areas of high atmospheric pressure located around 30 degrees latitude. The Westerlies have their origin from these subtropical highs and are a result of the pressure gradient between the subtropical highs and the sub polar lows.

Therefore, option 2 is correct as the Westerlies have their origin in the subtropical highs