The correct answer is: A. Marker
A semi-automatic signal is identified by a marker. A marker is a small, round, reflective device that is placed on the ground to indicate the location of a semi-automatic signal. Markers are typically yellow or orange in color and are often reflective to make them more visible at night.
Semi-automatic signals are used to control traffic at intersections where there is no traffic light or stop sign. When a semi-automatic signal is activated, it will typically display a flashing yellow light. This means that drivers should proceed with caution and yield to oncoming traffic.
Semi-automatic signals are a relatively new type of traffic control device, and they are not yet in widespread use. However, they are becoming more common, especially in areas with high traffic volumes.
Here is a brief explanation of each option:
- Option B: Semi marker. A semi marker is not a real thing. It is a made-up word that does not have any meaning in the context of traffic control.
- Option C: Illuminated a marker. Illuminated a marker is also not a real thing. It is a made-up phrase that does not have any meaning in the context of traffic control.
- Option D: None of these. This option is correct because the only option that is actually a real thing is option A.