A 78-year-old woman presents to her family physician's office with a chief complaint of fatigue and shortness of breath. The doctor indicates that he wants her to go to the hospital to get some pulmonary function tests, but there is one who is able to do in the office. A spirometer can be used to directly measure which of the following?
a. FRC
b. Peak flow rate
c. Residual volume
d. Total lung capacity
e. Vital capacity