Question

an air mass takes on its source regions
a. temperature and humidity
b. landforms and air pressure
c. clouds and wind
d. altitude and humidity

Explanation:

An air mass acquires the characteristics of its source region. Temperature and humidity are key properties determined by the source region (e.g., a warm, moist source region makes the air mass warm and moist). Landforms affect local weather but aren't "taken on" by the air mass as a whole. Clouds and wind are weather elements influenced by many factors beyond just the source region. Altitude isn't a property "taken on" in the same sense as temperature and humidity from the source region.

Answer:

A. temperature and humidity