What action is required at a four-way stop?

At a four-way stop, the action required is for the first vehicle to arrive to go first. This means that vehicles must stop at the intersection, and the driver who reaches the stop sign first is given the right of way to proceed through the intersection. This rule helps to maintain order and safety at intersections where multiple vehicles may be approaching from different directions.

It's essential for drivers to recognize that adhering to this rule prevents confusion and potential accidents, as all drivers can predict the movements of others based on arrival times. Following this guideline ensures that traffic flows smoothly and everyone is aware of who has the right to proceed.

The other options do not accurately capture the primary rule of right-of-way at a four-way stop, which is centered around arrival times rather than yielding or making assumptions based on turning or the presence of other vehicles.