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: Medicine
[{'content': 'NOT a feature of pleural effusion: September 2012 \nSelect and explain. \nA. Horizontal fluid level, B. Low lung volume, C. Muffled hea sounds, D. Decreased chest movements', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A i.e. Horizontal fluid level', 'role': 'assistant'}]