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: Anaesthesia
Optimum oxygenation is maintained by adjusting following parameters
a — Tidal volume,b — PEEP,c — FiO2,d — respiratory rate 
Select and explain. 
A. a, b, B. b, c, C. c, d, D. d, a
B: b, c
Answer: B: b, c 
Explanation: PEEP and FiO2 determine optimum oxygenation.