Which one of the following is NOT a favourable condition for occurrenc

Which one of the following is NOT a favourable condition for occurrence of a thunderstorm ?

Conditional and convective instability
Adequate supply of moisture in the lower atmosphere
Advection of cold dry air in the lower troposphere and warm moist air in the upper troposphere
A synoptic situation of low level convergence and upper level divergence
This question was previously asked in
UPSC CAPF – 2017
Thunderstorms require unstable atmospheric conditions, a source of moisture, and a lifting mechanism. Statement A describes conditional and convective instability, which is essential for strong vertical air movement. Statement B highlights the need for adequate moisture, which provides latent heat when it condenses, fueling the storm, and also provides the source for precipitation. Statement D describes a synoptic situation that leads to lifting (low-level convergence forces air up) and aids thunderstorm development (upper-level divergence helps remove rising air, maintaining ascent). Statement C describes a stable atmospheric condition where cold, dense air is below warm, less dense air. This stratification inhibits vertical air movement and is unfavourable for thunderstorm development.
Thunderstorms form in unstable atmospheric conditions where warm, moist air rises. A stable atmosphere with cold air below warm air inhibits this process.
The key ingredients for a thunderstorm are moisture, instability, and a lifting mechanism (like fronts, convergence lines, orographic lift, or simple heating). Instability is often provided by a steep vertical temperature lapse rate, where temperature decreases rapidly with height. Advecting cold dry air below warm moist air would create an inversion or stable layer, suppressing convection.
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