What defines the term "dry lines" in weather terminology?

"Dry lines" refer specifically to boundaries that separate moist air from dry air masses. This atmospheric feature is particularly important in meteorology, as these lines often play a crucial role in the development of severe weather, including thunderstorms. The dry air on one side can lead to the lifting of the moist air on the other side, which can result in condensation and precipitation, particularly in unstable atmospheric conditions.

Understanding dry lines helps meteorologists predict where thunderstorms are likely to occur, as the contrast in humidity and temperature often contributes to significant convective storms in the regions where these boundaries exist. This definition underscores the significance of moisture gradients in weather patterns, making option B the accurate representation of what dry lines are in the context of meteorology.