Phoenix hears voices in his head that tell him to punch holes in the walls of his room. Because Phoenix is perceiving the voices without an external auditory stimulus, he is experiencing

a. a delusion

b. a hallucination

c. apathy

d. loosening of associations

B.

Explanation:

Phoenix is experiencing a hallucination, which is defined as "an experience involving the apparent perception of something not present." In this case, Phoenix is perceiving voices in his head telling him to punch holes in the walls, while the voices are not present, they're in his head.