Picture yourself hiking in a narrow canyon in Utah. The canyon is dry and it hasn’t rained for weeks. You see some thunderhead clouds in the sky, but not one drop of rain all day. Nevertheless, a small rush of water starts to run through the canyon, turning it into a creek. There must have been a heavy rainfall somewhere nearby. Water runs down the sides of the canyon, forming little waterfalls. You realize that there could be a flash flood coming! You turn quickly up a side trail to higher ground before you are washed down the canyon.

What are the stimulus and response in this scenario?

A. The stimulus is the rain clouds and the response is the water in the canyon.
B. The stimulus is the appearance of water in the canyon and the response is moving to higher ground.
C. The stimulus is water running down the canyon walls and the response is little waterfalls forming.
D. The stimulus is the rain somewhere else and the response is you realize that there could be a flash flood.