Answer:
A
Step-by-step explanation:
A thunderstorm only occurs in cumulonimbus cloud.
A change in the wind direction and high speed winds at high altitudes makes the air to swirl around horizontally .
The air which rises from the ground tries to push up the air which is swirling around and tips it over.
The funnel of the air starts sucking up more warm air from the ground.
The funnel grows longer and longer and stretches to reach the ground and
when the funnel reaches the surface it becomes a tornado.