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: Radiology
[{'content': 'Initiator in developer solution is \nSelect and explain. \nA. Acetic acid, B. Sodium thiosulphate, C. Hydroquinone, D. Potassium bromide', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Developer\xa0converts\xa0exposed\xa0silver\xa0halide\xa0crystals\xa0into\xa0metallic\xa0silver grains. Two developing agents, usually phenidone and hydroquinone, are used in dental radiology.\nWhite and Pharoah, pg-69', 'role': 'assistant'}]