The correct answer is A. Cumulonimbus.
Explanation
Cumulonimbus, also called vertical development clouds, are a type of cloud that is characterized by expanding from the bottom up through the process of convection, that is, the sun's rays cause the water contained in the cloud to evaporate (take a gaseous state), in this way the water rises until it reaches a point where it condenses to precipitate, but different to other clouds it does not precipitate or become rain but the process is repeated making the cloud develop vertically. Additionally, the rains produced by these clouds are usually quite abundant accompanied by thunderstorms. So, the correct answer is A. Cumulonimbus.
