The Pilomotor Reflex Have You Ever Experienced the Pilomotor Reflex? Chances Are That

The Pilomotor Reflex
Have you ever experienced the pilomotor reflex? Chances are that you have. The pilomotor reflex is actually something most people experience every day: goosebumps.
Goosebumps (also called goose flesh and goose pimples) are small bumps on the skin. They are created when tiny muscles beneath the hairs on your skin contract, pulling the hair into an upright position. They can occur anywhere that you have hair on your body, but they are most common on your arms and legs. Goosebumps are an involuntary reaction to many different sensations, such as cold, fear, or even happiness.
Humans are not the only animals that get goosebumps. When cats or dogs are threatened by an enemy, the pilomotor reflex will cause their fur to stand on end. This makes the animal look larger, which might scare away the enemy. Porcupines also experience the pilomotor reflex; a frightened porcupine will raise its quills when it is in danger. This not only makes the porcupine look bigger, but it also frightens enemies away by drawing attention to the sharp quills. The pilomotor reflex can also help animals stay warm by trapping body heat closer to their skin.
Because human beings have much less body hair than most other animals, goosebumps do not make us seem larger or more intimidating. They also do not help to keep us very warm, although they do help to prevent some heat from leaving the body. For the most part, the pilomotor reflex is much more important for animals than it is for people. In fact, many scientists think that the pilomotor reflex is actually completely useless for humans.
Question: What is the best summary of this passage?

A) Humans have less hair than dogs or cats; therefore, the pilomotor reflex is not as obvious-or useful-in humans as it is in dogs or cats. Indeed, the reflex might be of no use at all in human beings.
B) When dogs or cats are threatened by a potential predator, the pilomotor reflex causes their hair to stand on end, often scaring off the enemy.
C) The contraction of tiny muscles under the skin that results in goosebumps can cause different sensations, including cold, fear or happiness.
D) The pilomotor reflex is a reaction to different sensations with effects ranging from bumps on the skin to fur or quills standing on end. Although it is probably not useful for humans, it is an important defensive tool for animals.