This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Physiology
TLC is: 
Select and explain. 
A. 4.2 lt, B. 3lt, C. 5lt, D. 6lt
D: 6lt
Answer: D: 6lt 
Explanation: TLC: the volume of air left in the lung at the end of maximal inspiration. TLC= TV+IRv+ERV+Rv Ref: G K Pal textbook of Practical physiology 4th edition, page number: 158,159