Wintertime MP Air Masses Are Less Common Along the Atlantic

Multiple Choice

Wintertime mP air masses are less common along the Atlantic coast of North America than along the Pacific coast mainly because

A) the water is colder along the Pacific coast.
B) the prevailing winds aloft are westerly.
C) the source region for mP air on the Atlantic coast is western Europe.
D) the water is warmer along the Atlantic coast.
E) the land is colder along the Atlantic coast.