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': 'Indicated mandibular major connector for a long span edentulous ridge: \nSelect and explain. \nA. Lingual plate, B. Lingual bar, C. Double lingual bar, D. Labial bar', 'role': 'user'}, {'content': 'Answer: A \nExplanation: When posterior teeth have been lost and there is a need for additional indirect retention, the use of a lingual\xa0plate may be advantageous.\nStewart’s Clinical Removable Prosthodontics. Edition 4. Page 33', 'role': 'assistant'}]