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': 'Indirect retainers are most effective when: \nSelect and explain. \nA. They rest bilaterally on cingulum of canines, B. Rest on mesial surface of premolars with extensions on to canines, C. They rest on incisal edges of canines, D. Rest on incisal edges of lateral incisors with extensions on to central incisiors', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]