The nurse knows that which of the following is not a cause of mastitis?

A. Engorgement → Correct; milk stasis increases infection risk. B. Cracked nipples → Correct; open skin allows bacteria to enter. C. Infrequent feedings → Correct; leads to milk stasis and possible infection. D. Gradual weaning → Incorrect; mastitis is caused by stagnant milk, but gradual weaning prevents engorgement and milk stasis.