This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Biostatistics, Subject name: Social & Preventive Medicine
[{'content': 'Degree of freedom for 2/2 contingency table is? \nSelect and explain. \nA. 1, B. Zero, C. 2, D. 4', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ref: Parks 23rd edition Degree of freedom = (r-1)(c-1) =(2-1)(2-1)= 1', 'role': 'assistant'}]