This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: New born infants, Subject name: Pediatrics
Most common cause of Per Rectal Bleeding in Infant ? 
Select and explain. 
A. Anal fissure, B. Rectal polyp, C. Intussusception, D. Hypeension
A: Anal fissure
Answer: A: Anal fissure 
Explanation: Anal fissures: These small tears are the most common cause of rectal bleeding in children. They can hapen when passing a large or hard stool, which stretches the lining of the anus until it tears, or when frequent diarrhea irritates the lining . Reference : page 126 Ghai Essential Pediatrics 8th edition