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
Normal vital capacity in an adult is 
Select and explain. 
A. 1200 ml, B. 2500 ml, C. 3000 ml, D. 4700 ml
D: 4700 ml
Answer: D: 4700 ml 
Explanation: Vital capacity Amount of air that can be exhaled with maximum effo after maximum inspiration (ERV + TV + IRV); used to assess strength of thoracic muscles as well as pulmonary function. Around 4700mlRef: Ganong review of medical physiology 23rd edition Page no: 593