Final answer:
The most appropriate response by the nurse would be to ask about when the pain started and what the patient was doing when it started.
Step-by-step explanation:
The most appropriate response by the nurse in this situation would be option c) 'When did the pain start? What were you doing when it started?' This response demonstrates the nurse's concern for the patient's well-being and the importance of collecting relevant information about the pain. By asking when the pain started and what the patient was doing when it started, the nurse can gather more information to make an assessment and provide appropriate care.