Choose the word which is different from the rest.

The answer is C. Identification.

An illusion is a false or misleading perception of reality. A delusion is a false belief that is not based in reality. A hallucination is a sensory experience that occurs in the absence of a stimulus. Identification is the process of recognizing and understanding the similarities and differences between oneself and others.

In the context of the question, identification is the only word that does not describe a perceptual or cognitive phenomenon. The other three words all describe ways in which people can perceive or understand the world around them inaccurately.