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: Biochemistry
[{'content': 'A 40 year old male patient complains of diminished vision during night and dryness of eyes. Patient gives history of recurrent bacterial infections. Ophthalmic examination reveals white triangular plaques on conjunctiva. This patient is suffering from deficiency of: \nSelect and explain. \nA. Vitamin D, B. Vitamin B, C. Vitamin A, D. Vitamin C', 'role': 'user'}, {'content': "Answer: C \nExplanation: Night blindness (nyctalopia) is\xa0one\xa0of\xa0the\xa0earliest symptoms\xa0of\xa0vitamin\xa0A\xa0 deficiency. Severe deficiency of\xa0vitamin\xa0A\xa0leads to xerophthalmia. This is characterized by dryness in conjunctiva and cornea, and keratinization of epithelial cells. In certain areas of conjunctiva, white triangular plaques known as Bitot's spots are seen.\nSatyanarayana- Biochemistry, 3rd edition, pg-123", 'role': 'assistant'}]