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': 'In the cast restoration, cusp protection is mandatory when: \nSelect and explain. \nA. The lesion depth is ⅓  to ½ the intercuspal distance, B. The lesion depth exceeds ½ the intercuspal distance, C. The lesion width is ⅓  to ½ the intercuspal distance, D. The lesion width  exceeds ½ the intercuspal distance', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Indications:\n\nIf the width of the lesion is 1/3 to 1/2 the intercuspal distance - cuspal protection is to be considered.\nIf the width of the lesion exceeds 1/2 the intercuspal distance - cuspal protection is mandatory.\nIf the length:width of the cusp is more than 1:1, but not exceeding 2:1 - cuspal protection is to be considered.\nIf the length:width of the cusp is more than 2:1 - cuspal protection is mandatory.\nWhen there is a need to change the dimension, shape and interrelationship of the occluding tooth surfaces.\n\nMDS Prep Bytes( Cast Restoration – Onlay)', 'role': 'assistant'}]