This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous System, Subject name: Physiology
[{'content': 'Transducin is required for \nSelect and explain. \nA. Smell, B. Hearing, C. Taste, D. Vision', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. (d) Vision(Ref: Ganong, 25th ed/p. 178)The G protein coupled receptor in rods is called "Transducin\'\'Role of transducin is to activate the enzyme phosphodiesterase that degrades cGMP', 'role': 'assistant'}]