Which of the following is a type of air mass?

Maritime Polar is indeed a recognized type of air mass. Air masses are classified based on their source regions and can be categorized by their moisture content and temperature characteristics. The "maritime" designation indicates that the air mass originates over oceans or large bodies of water, resulting in higher moisture content. In this case, "polar" specifies that this air mass hails from high-latitude regions, meaning it is typically cold.

The other options listed do not conform to the established classifications of air masses. Desert Polar, for instance, is not a recognized type because deserts are typically associated with dry conditions, while "polar" suggests cold, moist air. Continental Arctic is a valid type of air mass, but it describes a different characteristic, focusing on land-based (continental) origins and very cold conditions. Mountain Tropical also does not represent a standard classification, as tropical air masses typically come from warmer regions and do not specifically pertain to mountainous areas.

Understanding these classifications is essential for interpreting weather patterns and predicting changes based on the movements of various air masses.