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
In an emphysematous patient with humus leison which is the best investigation to measure lung volumes ? 
Select and explain. 
A. Body plethysmography, B. Helium dilution, C. Trans diaphragmatic pressure, D. DLCO
A: Body plethysmography
Answer: A: Body plethysmography 
Explanation: None