Final answer:
The client understands preoperative teaching about pain management when they state that they will request pain medication if their pain increases.
Step-by-step explanation:
The correct statement that indicates the client understands preoperative teaching about pain management is a. "I'll request pain medication if my pain increases." This statement shows that the client recognizes the importance of monitoring their pain levels and taking action to alleviate their discomfort. They understand that pain medication should be requested if the pain becomes worse.