This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
At what age baby with congenital hypertrophic pyloric stenosis show symptoms 
Select and explain. 
A. At the time of birth, B. First week, C. 3rd to 4th week, D. Second month
C: 3rd to 4th week
Answer: C: 3rd to 4th week 
Explanation: Baby show the symptoms of projectile vomiting, olive shaped mass and visible peristalsis