system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 2-day-old newborn is brought to the physician because of vomiting. Physical examination shows a small mass about the size of an olive in the epigastric area. 

Which of the following conditions is this child likely to exhibit?
assistant
The correct answer is  None