Context: Air masses influence weather everywhere on Earth. But air masses can form only over certain places. These places are known as air mass source regions.
Source regions are places that have low wind speeds for days or weeks at a time. When wind speeds are low, air above the source region remains in place. When air remains in place, it can take on the features of the source region. For example, air that remains over a warm source region can increase in temperature as the air gains thermal energy from Earth's surface.
The map below shows wind speeds in Earth's lower atmosphere on March 1, 2017. Two areas, labeled A and B, are outlined on the map.
Data source: United States National Oceanic and Atmospheric Administration/Earth System Research Laboratory, Physical Sciences Division
Based on the wind speeds measured this day, which area was more likely to be an air mass source region?
A. Area B
B. Area A
From the given choices, choose the correct answer and respond with the letter of that choice.

B