This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Growth and development, Subject name: Pediatrics
[{'content': 'A child can withhold and postpone his/her bowel movements at _______ \nSelect and explain. \nA. 1 year, B. 2 years, C. 3 years, D. 4 years', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Encopresis is defined as passage of stools in clothes beyond an age when bowel control should have been achieved (usually 4 years). It may be retentive (associated with constipation) or non-retentive, primary (never achieved bowel control) or secondary (loss of control after an initial phase of control for at least 6 months). Primary encopresis is usually associated with constipation, while secondary is associated with significant psychological stressors. Behavioral therapy with positive reinforcement and treatment of constipation are necessary. Ref : Nelson paediatrics chapter : Groth and de', 'role': 'assistant'}]