During CPR, a Properly Positioned Endotracheal Tube Can Do Which

During CPR, a properly positioned endotracheal tube can do which of the following?
1) Isolate and protect the lower airway from aspiration.
2) Permit suctioning of the trachea and main stem bronchi.
3) Facilitate positive-pressure ventilation and oxygenation.
4) Provide a route for administration of selected drug agents.

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