It Is Important to Monitor Lung Volumes in ICU Patients

It is important to monitor lung volumes in ICU patients because changes in lung volumes reflect which of the following changes?
1) Changes in gas exchange in the lung.
2) Changes in the patient's clinical status.
3) A response to therapy and any problems that may arise.
4) They influence the selection of antibiotic therapy in the ICU.

A) 1 and 4
B) 2 and 3
C) 1, 2, and 3
D) 2, 3, and 4