A nurse is presenting an in-service about the use of postural drainage for infants who have cystic fibrosis. Which of the following positions should the nurse identify as being contraindicated for the infant?

A. Sitting on a nurse's lap leaning forward is a safe position for postural drainage as it promotes drainage from the upper lobes of the lungs. B. The Trendelenburg position, where the body is laid flat on the back with the feet higher than the head, is contraindicated for infants with cystic fibrosis because it can increase the risk of gastroesophageal reflux and aspiration. C. The supine position is generally safe but does not facilitate effective postural drainage compared to other positions. D. Sitting on a nurse's lap leaning backward is safe and can be used for drainage from the anterior lung segments.