The nurse is caring for an infant admitted with dehydration, irritability, signs of extreme hunger, and a palpable olive-like mass in the upper right abdominal quadrant. When feeding the infant, the nurse should monitor for which development?

A. Arched back: Arching the back may occur with gastroesophageal reflux or pain but is not the defining sign of pyloric stenosis, which is the likely condition indicated by the olive-like mass and hunger after vomiting. B. Projectile vomiting: Pyloric stenosis causes hypertrophy of the pyloric sphincter, obstructing gastric emptying and leading to forceful, projectile vomiting after feeding. The infant remains hungry afterward due to incomplete digestion and absorption. C. Frequent pauses: Frequent pauses during feeding may indicate feeding fatigue or poor coordination, more typical of premature infants or cardiac conditions, not pyloric stenosis. D. Coffee-ground emesis: This suggests gastrointestinal bleeding, which is not characteristic of pyloric stenosis. The vomitus in pyloric stenosis is typically non-bilious and contains undigested milk.