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': 'If the extension of a cavity from a primary groove towards the cusp tip is more than 2/3 then: \nSelect and explain. \nA. No cusp capping., B. Consider capping., C. Cusp capping mandatory., D. None', 'role': 'user'}, {'content': 'Answer: C \nExplanation: If the extension of a cavity from a primary groove towards the cusp tip is', 'role': 'assistant'}]