This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': "An examiner wants to study two groups of infants for 50 each, CPAP and double tests were performed, in 30 infants CPAP was positive and in 20 bubble test was positive, what should be the test used in this case? \nSelect and explain. \nA. Chi square test, B. Student's test, C. Paired t test, D. Coefficient of variance", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]