Final answer:
A large air mass with high temperature and low humidity is known as a continental tropical (cT) air mass.
Step-by-step explanation:
If a large body of air has a high temperature and a low relative humidity, then the air mass is called continental tropical (cT). This type of air mass originates over large land masses in the tropics or subtropics and is characterized by hot air and little moisture. The other options provided refer to different characteristics: continental arctic (cA) would be very cold and dry, continental polar (cP) would be cold but not as cold as cA, whereas maritime polar (mP) and maritime tropical (mT) originate over oceans, with mP being cool and moist and mT being warm and moist.
Type D climates are known as cold or continental climates and exhibit more extreme temperature variations with cool to hot summers and cold winters. Precipitation can vary, falling as rain in the summer and snow in the winter. This climate type is frequently found in regions situated in the interiors of large continents and farther away from the equator than type C climates.