A home health nurse is caring for a client who has emphysema and has difficulty with mobility. The client spends most of his day in a reclining chair. Which of the following physiological responses to prolonged immobility should the nurse expect?

A. Prolonged immobility leads to bone demineralization, causing increased calcium excretion in the urine, which can contribute to osteoporosis and kidney stone formation. B. Sodium excretion is not significantly decreased solely due to immobility; fluid balance may be affected, but this is not a primary response. C. Immobility does not increase insulin production; in fact, decreased physical activity can contribute to insulin resistance over time. D. Red blood cell production may decrease slightly due to reduced erythropoietin stimulation from immobility, but increased calcium excretion is a more direct and expected physiological response.