What is the first stage of a thunderstorm?

cumulonimbus stage

mature stage

cumulus stage

dissipating stage

Cumulus stage

Explanation:

Most electrical storms form from stages, their first stage is cumulus:

In this stage, the sun warms the surface of the earth, this makes the heat from the surface warm the nearby air, as the hot air is lighter than the cool it begins to rise. If the air is humid, then the hot air condenses into a culumus cloud. The cloud will continue to grow as long as the hot air continues to rise.