What would be the best flow rate of o2 for a patient with copd? 2 liters per minute or 5 liters per minute?

Im pretty sure the answer is 2 liters per minute via nose canula. it would be 4 liters via mask.
this is starting out, anyway. as copd gets worse, the oxygen flow needs to be raised. so ultimately the flow rate depends on how much oxygen the individual's body needs in order to keep the o2 saturation level between 88 and 92.

Ithink the correct answer is c

Awould be the most dangerous