Final answer:
A nurse assessing for nail clubbing should examine the angle of the nail base, as clubbing is indicated by an increased curving of the nail and an angle greater than 160 degrees.
Step-by-step explanation:
The nurse assessing a patient for nail clubbing should focus the exam on the angle of the nail base (D). Nail clubbing is a change in the structure of the fingernail or toenail in which the nail becomes enlarged and the nail plate becomes more convex. It is often a sign of various types of lung disease but can also be associated with liver disease, gastrointestinal disorders, heart disease, and other conditions. During the assessment, the healthcare provider will look for an increased curving of the nail, which is measured by the angle between the nail base and the skin. This angle, in the case of clubbing, will be greater than the normal 160 degrees. Additionally, the nurse may look for other signs associated with clubbing, such as the softening of the nail bed and increased sponginess of the nail base.