What is the officer indicating?

What is the officer indicating?
A)That all road users approaching the officer must stop.Correct
B)Resume the journey.
C)That all drivers approaching the officer must stop.
An officer with the arm raised vertically requires all road users approaching the officer to stop, except drivers who cannot do so safely.
The stop must be made before the nearest stop line or, failing that, immediately before the officer.
At an intersection, the stop must be made before entering it.
After this signal, the officer may, where appropriate, indicate the place where the stop must be made.