This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
A term baby girl has two episodes of bile-stained emesis at 24 hours after bih. There is a history of excessive amniotic fluid volume. The most appropriate diagnostic test is? NOT RELATED - MEDICINE 
Select and explain. 
A. Blood culture, B. Barium swallow and Gastrointestinal X rays, C. CT scan of head, D. Neurosonogram
B: Barium swallow and Gastrointestinal X rays
Answer: B: Barium swallow and Gastrointestinal X rays 
Explanation: .