Flood - A flood is a normal, common disaster when it rains so heavy, that rivers began to overflow. They're very common throughout the United States, but it isn't common if states don't have any lakes or streams, but it can still happen. When lake or streams get flooded, the national weather service will issue a flood warning.
Flash Flood - A flash flood, still common, is a overflow of rapid water, that can move at 2.7 meters per second! They're known to occur at mountain ranges and arid plains. A flash flood can be more dangerous than a original flood, because the rapid water speeds can sweep you away with the water. Even if you try to swim, you won't be able to get out.
The answer to your question is C
