pick from the following. A. murmur. B. reflexes. C. vehicles. D. movement. E. rain. F. photons. G. waves. H. an object.

You are presented with the quiz "what can animals be startled by?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "loud noises can cause animals to startle" and "all animals are startled by an unannounced approach, a sudden movement, or a loud noise". So, what's the best answer to the question?
Answer:
D.