As You Walk into Your Dorm Room,you Notice That Your

As you walk into your dorm room,you notice that your roommate is crying.Why is it difficult to know if she is happy or sad?

A) Her facial expressions are likely to be similar.
B) Her physiological reactions are likely to be similar.
C) Her nonverbal cues are likely to be similar.
D) None of the above; it should be easy to differentiate between happiness and sadness.