To Protect Oneself from Infection, Pulmonary Function Testing Should Be

To protect oneself from infection, pulmonary function testing should be conducted using which of the following precautions?
1) Standard precautions on all patients
2) Airborne precautions on all patients
3) Handwashing in between patients
4) Handwashing after handling used circuit components

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