3-day-old boy evaluated for bilious emesis. Symptoms include abdominal distension, hypoactive bowel sounds, failure to pass meconium in the first 48 hours of life, and explosive expulsion of gas & stool during rectal exam. Diagnosis?
a. Hirschsprung's disease
b. Intussusception
c. Malrotation with volvulus
d. Necrotizing enterocolitis (NEC)