A nurse is caring for a 3-day-old newborn and suspects Hirschsprung disease. What finding best supports the nurse's concern?

A. Passing tar-like stools is normal for newborns within the first few days of life and does not indicate Hirschsprung disease. B. Limited stooling and poor weight gain may suggest feeding issues but are not as indicative of Hirschsprung disease as the absence of stool. C. The absence of stool (failure to pass meconium within 24-48 hours) is a classic sign of Hirschsprung disease, a condition where the absence of ganglion cells in the intestines leads to a blockage. D. Passing hard, pellet-like stools may indicate constipation but is not specific to Hirschsprung disease, especially in a newborn.