Army Reserve Soldier

It is now the next morning and you have been called out on a task, having been given the following orders:
Ground: You are manning a vehicle checkpoint on the edge of the city.
Situation: Local militiamen involved in arson are attempting to escape arrest by fleeing the city. A list of number-plates of known militia vehicles has been passed to you by Intelligence Personnel.
Mission: Stop these vehicles and detain the occupants.
A car containing two local men approaches. You stop the car and check the plate against your list but it doesn't match.
The two men seem nervous and agitated so you decide to investigate further and ask them to step out of the vehicle.
They do so reluctantly and their clothes smell of petrol.
What should you do next?
a. Search the two men to ensure that they are not armed.
b. Search the vehicle for further evidence.
c. Radio Headquarters to let them know what is going on.
View the answer.