Final answer:
The nurse should assess a client's skin turgor by pinching the skin over the sternum, as it provides a reliable indicator of hydration levels.
Step-by-step explanation:
To assess a client's skin turgor, a nurse should gently pinch and release the skin, typically in an area where the skin is thin and can be easily lifted. The correct method to assess skin turgor, in this case, would be to pinch the skin over the sternum (A). This location provides a reliable assessment as the skin is usually not affected by significant changes in fat deposits that could affect the turgor. Assessing skin turgor is a common technique used to evaluate the level of hydration in a patient as it helps to determine if the skin promptly returns to its original position (normal turgor) or if it returns slowly, indicating potential dehydration.