You and your partner are the first emergency personnel on the scene of an overturned tanker truck. The driver appears motionless in the cab of the vehicle. You also note liquid leaking from the rear-valve assembly of the tanker trailer.
After properly positioning your ambulance, your immediate priority is to:

A) take manual in-line spinal stabilization on the driver.
B) evacuate people from cars near the tanker.
C) assess the driver for life-threatening conditions.
D) determine what chemical is contained in the tanker.