Description:

The correct answer is:

Cumulonimbus

Cumulonimbus clouds are often called "thunderheads" because they are directly associated with thunderstorms. These towering, anvil-shaped clouds produce heavy rain, lightning, hail, and sometimes tornadoes.

Stratus – Low, flat, gray clouds that typically bring drizzle or overcast skies.

Cirrus – Thin, wispy, high-altitude clouds made of ice crystals, not storm-related.