This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Tumors, Subject name: Ophthalmology
[{'content': 'The commonest malignant tumour of the lids is \nSelect and explain. \nA. Basal-cell carcinoma, B. Squamous cell carcinoma, C. Adenocarcinoma, D. Melanocarcinoma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: MALIGNANT TUMOURS Basal-cell carcinoma It is the commonest malignant tumour of the lids (90%) usually seen in elderly people. It is locally malignant and involves most commonly lower lid (50%) followed by medial canthus (25%), upper lid (10-15%) and outer canthus (5-10%). Clinical features: It may present in four forms: Noduloulcerative basal cell carcinoma is the most common presentation. It stas as a small nodule which undergoes central ulceration with pearly rolled margins. The tumour grows by burrowing and destroying the tissues locally like a rodent and hence the name rodent ulcer. Ref:- A K KHURANA; pg num:-360', 'role': 'assistant'}]