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: Microbiology
[{'content': "All of the following statements about 'yaws' are true except - \nSelect and explain. \nA. Caused by Treponema pertenue, B. Transmitted non venerally, C. Secondary yaws can involve bone, D. Late stages of yaws involve heart and nerves", 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]