This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thorax, Subject name: Anatomy
[{'content': 'Posterior to sternum is \nSelect and explain. \nA. Left atrium, B. Left ventricle, C. Right atrium, D. Right ventricle', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Posterior to sternum is right ventricle . Ref - medscape.com', 'role': 'assistant'}]