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': 'By 2 weeks of age, infants normally show all of the following signs Except \nSelect and explain. \nA. Copying facial expression, B. Stepping, C. Palmar grasp, D. A negative Babinski reflex', 'role': 'user'}, {'content': 'Answer: D \nExplanation: By 2 weeks of age, infants show stepping, palmar grasp, the rooting reflex, and the copying of facial expressions. The Babinski reflex is normally positive until a child is approximately 12 months of age. Ref: Nelson paediatrics; Table 11-1', 'role': 'assistant'}]