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': 'The property of an index to measure what is intended to measure is known as \nSelect and explain. \nA. Validity, B. Reliability, C. Quantifiabitity, D. Sensitivity', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]