How Can You Ensure Reliability When Measuring the Expiratory Reserve

Multiple Choice

How can you ensure reliability when measuring the expiratory reserve volume (ERV) ?

A) Have the patient perform the maneuver twice, ensure consistency, then take the best value.
B) Have the patient perform the maneuver three times, and then take the last value.
C) Have the patient perform the maneuver twice, ensure consistency, then take the mean value.
D) Have the patient perform the maneuver until he or she becomes fatigued, and then take the last value.