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': 'When sample size is small and observations are dependent of each other, which test is used for significance of difference between two mean? \nSelect and explain. \nA. Fisher test, B. Unpaired —t test, C. Paired — t test, D. Z-test', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]