What must NOT be happening for a vehicle to be legally parked on the street?

Answer: A — Obstructing traffic

For a vehicle to be legally parked on the street, it must not be obstructing traffic. This means that the parked vehicle cannot impede the flow of vehicles or pedestrians using the roadway. When a vehicle blocks traffic, it creates dangerous situations and can lead to accidents or delays. In contrast, being out of gas, being on the shoulder, or not running doesn't automatically designate a vehicle as illegally parked. A vehicle could technically be parked on the street even if it is not currently operational or is out of gas, as long as it's not causing an obstruction. However, the legality of parking on the shoulder can depend on local regulations, so it’s important to be aware of specific laws in your area regarding shoulder parking.