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': 'Which is Not required for visualisation of gall bladder in oral cholecystography: \nSelect and explain. \nA. Functioning liver, B. Motor mechanisms of gall bladder, C. Patency of cystic duct, D. Ability to absorb water', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Motor mechanism of Gall bladdar Oral Cholecystography (Graham - Cole - Test) OCG was introduced in 1924 by Graham & Cole. - Na/Ca-Iopanoic acid (TelepaqueQ / Biloptin/ Solubiloptine) dye is used as contrast media. - 3 gmQ of dye is given & X Rays are taken at an interval of 12-15 hours. - USG has replaced itQ.', 'role': 'assistant'}]