A nurse is teaching a client how to use a diaphragm. Which of the following statements should the nurse include in the teaching?

A. The diaphragm should be inserted after emptying the bladder to reduce the risk of urinary tract infections. B. Baby powder should not be applied to the diaphragm as it can cause irritation or damage. C. Oil-based lubricants can degrade latex diaphragms and reduce their effectiveness; only water-based lubricants should be used. D. The diaphragm should be left in place for at least 6 hours after intercourse, not just 4 hours, to ensure effective contraception.