In a tiered-response EMS system:

A) every ALS ambulance that responds has at least three paramedics on board.
B) an ambulance with two paramedics makes the initial response to every EMS call.
C) an EMS system attempts to assign ALS ambulances only where they are needed.
D) a first response vehicle, BLS ambulance, and ALS ambulance respond to every call.

Answer: C) an EMS system attempts to assign ALS ambulances only where they are needed.