Must you yield to a fire service vehicle that is using only its special flashing light (without the siren)?

Why this is the correct answer

When a priority vehicle (fire service, police, ambulance) activates its special flashing blue light (V-1 signal), it is considered to be on emergency duty, even if the siren is not in use. The siren is an additional acoustic warning that must be used together with the light as a general rule, but there is an exception: when not using the siren poses no danger to other road users, the driver of the priority vehicle may use the light alone. This does NOT mean the vehicle has lost its priority status — it is still on emergency duty and you must yield to it. Therefore, option A is correct: the flashing light alone is enough to indicate emergency status. Option B is wrong because priority vehicles only have priority when they are on emergency duty (with signals activated), not at all times. Option C is wrong because the absence of the siren does not cancel the vehicle's emergency status; the special light by itself is sufficient.