What is this officer signalling?

What is this officer signalling?
A)It gives way to vehicles approaching the officer head-on.
B)It prohibits passage to all road users.
C)It requires vehicles approaching the officer from the front or rear to stop.Correct
The officer requires all road users approaching from directions that cross the one indicated by the extended arm or arms to stop, regardless of their direction of travel.
This signal remains in effect even if the officer lowers the arm or arms, as long as they do not change position or make another signal.

If the officer raises one arm vertically (Image 1), all road users approaching the officer must stop, except for drivers who cannot do so safely.
The stop must be made at 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 indicate, if applicable, the place where the stop must be made.

If the officer moves the arm alternately up and down (Image 2), drivers approaching the officer on the side corresponding to the arm making the signal, and perpendicular to that arm, must reduce their vehicle's speed.

The swinging of a red or yellow light (Image 3) requires road users toward whom the officer directs the light to stop.