Final answer:
The leading edge of a mass of cold air is known as a cold front, and it is associated with mid-latitude wave cyclones, often leading to a line of showers and thunderstorms.
Step-by-step explanation:
The leading edge of a mass of cold air is known as a cold front. It is associated with mid-latitude wave cyclones. When a cold front moves into an area, it undercuts the warmer air in front of it, leading to upward motion that can result in a line of showers and thunderstorms.
These weather events are often preceded by high winds, cooler temperatures, and clear skies once the front has passed. Therefore, the correct answer to the student's question is B) Cold front; associated with mid-latitude wave cyclones.