This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Photosensitive Disorders, Subject name: Skin
[{'content': 'Which of the following produces pre-malignant lesions - \nSelect and explain. \nA. Psoriasis, B. Erythema multiforme, C. Lichen planus, D. All of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans is \'c\' i.e. Lichen planus "Oral LP, particularly the erosive (ulcerative variant) is prone to develop SCC, the frequency being 0.8%. Long standing disease and concurrent use of tobacco are the risk factors for malignant transformation. Tongue is the most common site for malignancy, followed by buccal mucosa." - IADVL text book of dermatology 3rd/e p. 1074', 'role': 'assistant'}]