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: Ophthalmology
[{'content': "The earliest clinical manifestation of siderosis bulbi is: \nSelect and explain. \nA. Rusty deposits in the anterior subcapsular cells of the lens, B. Discolouration of iris, C. Deposits in Descemet's membrane of cornea, D. Pigmentary changes in retina", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Rusty deposits in the anterior subcapsular cells of the lens', 'role': 'assistant'}]