This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pediatrics
[{'content': 'At what age child begins to use past and present tense \nSelect and explain. \nA. 1 Years, B. 2 Years, C. 18 Months, D. 30 Months', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Begin to identify objects from a group by their function and pas (ie. "which one has wheels", "which one can we eat") Begin to use verbs with "ing" endings (i.e. "eating"); Early concepts such as "big, little" are identified; Child will use "no, not" and answer "where" questions Reference: GHAI Essential pediatrics, 8th edition', 'role': 'assistant'}]