Client satisfaction surveys from a surgical unit indicate that pain is not being adequately relieved during the first 12 hr postoperatively. The unit manager decides to identify postoperative pain as a quality indicator. Which of the following data sources will be helpful in determining the reason why clients are not receiving adequate pain management after surgery?

a. Pain assessment policy.

b. Postoperative care policy.

c. Prospective chart audit.

d. Retrospective chart audit.