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
TRUE/FALSE about features of Pyloric stenosis: 1. Hypokalemic alkalosis 2. Peristalsis right to left 3. Commonly caused by carcinoma stomach 4. Retention vomiting is present 5. Commonly females are affected 
Select and explain. 
A. 1,2,3 true & 4,5 false, B. 1,2,5 true & 3,4 false, C. 1 true 2,3,4,5 false, D. All are true
C: 1 true 2,3,4,5 false
Answer: C: 1 true 2,3,4,5 false 
Explanation: Hyperophic pyloric stenosis is more common in males. Male : female incidence is 4:1. Peristalsis is seen from left to right across the upper abdomen. Retention vomiting means vomiting due to any mechanical obstruction occurring usually hours after ingestion of a meal. In hyperophic pyloric stenosis the vomiting usually occur 10 to 30 min after the feed. Ref: Nelson 17/e, Page 1229