The nurse observes the presence of brittle, concave curves to the nails of a client on assessment. Which information should the nurse obtain from the client that may explain the appearance of the nails?

A. A recent Candida infection could affect the nails, but it typically causes nail thickening and discoloration rather than brittle, concave nails. B. Diabetes mellitus can lead to various nail changes, including thickening and yellowing, but it is not commonly associated with brittle, concave nails. C. Coronary heart disease may cause changes in the nails due to poor circulation, but it is not specifically linked to brittle, concave nails. D. Iron deficiency anemia is commonly associated with brittle, concave nails, a condition known as koilonychia. This nail abnormality is a classic sign of iron deficiency and warrants further investigation.