Which cloud type is typically associated with thunderstorms?

Cumulonimbus clouds are towering and dense clouds that are primarily associated with severe weather phenomena, including thunderstorms. These clouds have a characteristic anvil-shaped top and can reach high altitudes, making them capable of producing severe weather conditions such as heavy rain, lightning, hail, and even tornadoes. The vertical development of cumulonimbus clouds allows for strong updrafts and downdrafts, which are crucial for the formation of thunderstorms.

Other cloud types listed do not have the same association with thunderstorms. Stratus clouds are generally low, overcast layers that can produce light rain or drizzle, but they lack the vertical development necessary for thunderstorms. Cirrus clouds are high-altitude clouds composed of ice crystals and are typically indicative of fair weather, though they can signal changes in weather patterns. Stratocumulus clouds are low, lumpy clouds that usually do not produce significant precipitation or the intense conditions associated with thunderstorms. Cumulonimbus clouds stand out as the primary cloud type for stormy weather, making them the correct answer in this context.