A 3.3 kg, 36-week baby girl was born prematurely after labor caused by ruptured membranes. The prenatal ultrasound revealed a polyhydramnios at 26 weeks. Fetal echocardiogram was normal and amniocentesis was without genetic aberrance. On examination there was a normal anus, an nasogastric tube (NGT) drained bile stained fluid. The baby passed some mucus from below but no typical dark meconium. A chest and abdominal x-ray showed a "double bubble sign". What is the most likely diagnosis?