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Question

In a Stable air mass

A Thunderstorms Develop

B. There are large day to day temperature Changes

C Winds are very strong

Answer 1

Thunderstorms need an unstable air mass to develop.  Winds may be strong, but very strong winds are generally caused by a storm system which by definition is unstable.  

So the answer is B. There are large day to day temperature changes.

This happens because in a stable air mass there is a lack of clouds and moisture that causes rapid cooling after sundown and rapid warmup during the day.  You see this a lot in a desert climate.