Final answer:
The nurse should observe the client during movement of affected joints to assess pain and range of motion in osteoarthritis.
Step-by-step explanation:
In conducting a pain assessment of a client with osteoarthritis, the nurse should include observing the client during movement of affected joints, which is option d. This is important because it helps the nurse assess the client's range of motion, any visible signs of pain or discomfort during movement, and any noticeable joint deformities. It provides valuable information about the severity and impact of osteoarthritis on the client's daily functioning.