Convective Instability Associated with Severe Thunderstorms and Tornadoes Can Be

Multiple Choice

Convective instability associated with severe thunderstorms and tornadoes can be brought on by

A) lifting a stable air layer whose surface is humid and whose top is dry.
B) forcing a layer of moist air to descend a mountain range.
C) heating the upper portion of an unsaturated layer of air.
D) all of the above