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: Physiology
[{'content': 'Effort during normal respiration is done due to \nSelect and explain. \nA. Lung elasticity, B. Respiratory air passages, C. Alveolar air spaces, D. Creating negative pleural pressure', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]