Final answer:
Maritime Tropical (mT) air masses are based on moisture content and originate from warm ocean waters. They are warm, humid, and often bring precipitation to the areas they affect. The other air mass classifications mentioned are based on temperature characteristics.
Step-by-step explanation:
The air mass classification based on moisture content is Maritime Tropical (mT) because it originates from warm ocean waters and therefore contains a significant amount of moisture.
Maritime Tropical air masses are typically associated with warm and humid conditions, and they often bring precipitation to the areas they affect.
Maritime air masses, such as mP and Maritime Tropical (mT), form over water and are humid. Continental air masses, such as Continental Tropical (cT) and Continental Polar (cP), form over land and are typically dry.
On the other hand, the other air mass classifications mentioned in the options—Continental Tropical (cT), Maritime Polar (mP), and Continental Polar (cP)—are based on temperature characteristics rather than moisture content.
Therefore answer is d) Maritime Tropical (mT).