When approached by another vehicle at a stop sign, what is vehicle 1 required to do?

Answer: A — Yield the right-of-way

When a vehicle approaches a stop sign, it is required to yield the right-of-way to any other vehicle that is already in the intersection or approaching closely enough that it poses a risk. This means that if vehicle 1 reaches the stop sign at the same time as another vehicle, vehicle 1 must stop and allow the other vehicle to pass safely before proceeding. The intent of this rule is to prevent accidents and ensure safe interactions at intersections. Yielding the right-of-way fosters cooperation among drivers and helps manage traffic flow, especially at potentially hazardous intersections. The other options do not adhere to traffic rules governing right-of-way at stop signs, which is why they do not serve as the correct course of action.