This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastrointestinal tract, Subject name: Pediatrics
Which of the following drug will cause hyperophic pyloric stenosis is __________ 
Select and explain. 
A. Vancomycin, B. Nefidipine, C. Erythromycin, D. Phenyl propanolamine
C: Erythromycin
Answer: C: Erythromycin 
Explanation: The usual age of presentation is approximately 2 - 6 weeks of life. Approximately 95% of infantile hyperophic pyloric stenosis cases are diagnosed in those aged 3-12 weeks. In addition, premature infants have a delayed diagnosis secondary to low bih weight and atypical presentation. Reference: GHAI Essential pediatrics, 8th edition