The Nurse Is Working at a Pain Clinic and Is

The nurse is working at a pain clinic and is preparing an orientation for new staff nurses. Which of the following definitions of pain would the nurse correctly choose to include in this orientation?

A) Pain is validated by the nurse determining the cause of the pain.
B) Pain is an unpleasant sensation, typically experienced upon movement.
C) Pain is whatever the experiencing person says it is.
D) Pain is very subjective, so observations must be used to assess levels and intensity.