A six week old infant is brought to the emergency department by his parents because he has had vomiting after each feeding during the past three weeks. The patient is the parents first born, and they say they are not sure whether the vomiting is normal. Since the vomiting began, it has been worsening; it is now projectile and streaked with blood. The patient also has had enlarged abdomen, fewer, bowel movements, and weight loss. He is otherwise healthy,And immunizations are up-to-date. Family history includes similar symptoms in the patient's father when he was an infant. Current weight is 8 lbs. 13 oz. birth weight is 7 pounds temperature is 99.1\deg F. Directly, heart rate is 160 per minute, and respirations are 35 per minute. On physical examination, the interior Fontenelle is slightly sunken and the nasal and oral mucosa are dry. The upper abdomen is distended, and a small, round mass is palpated in the subxiphoid region. Barium swallow, x-ray study shows decreased gastric emptying. Which of the following is the most likely diagnosis? A incarcerated hiatal hernia B in interception C pyloric stenosis, D small bowel obstruction or E volvuluse.?