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: Medicine
Which of the following is most characteristic of congenital hyperophic pyloric stenosis? 
Select and explain. 
A. Affects the first born female child, B. The pyloric tumour is best felt during feeding, C. The patient is commonly marasmic, D. Loss of appetite occurs early
B: The pyloric tumour is best felt during feeding
Answer: B: The pyloric tumour is best felt during feeding 
Explanation: Congenital hyperophic pyloric stenosis is more common in first born males.Symptoms usually sta after 3 weeks of age.Nonbilious vomiting is the initial symptom. After vomiting, the infant becomes hungry and wants to feed again.The metabolic disturbance is hypochloremic metabolic alkalosis.Clinical diagnosis is by palpation of hyperophic mass, confirmed by USG.The surgical procedure of choice is Ramstedt pylorotomy.Ref: Nelson 17th/e p1229