Why must you be ready to brake in this situation?

In this situation, the correct answer is because the other vehicle might continue moving. On German roads, you must always be alert to changing traffic situations, especially when there is a vehicle that is parked or standing near the edge of the road. Even if it appears to be stationary, it could suddenly pull back onto the roadway or its driver could open a door, creating a hazard. That's why you are required to be ready to brake—to react safely if the other vehicle moves unexpectedly.

The other options, such as needing to brake specifically because of the direction of the road or a speed limit, are not the main reasons in this case. The most important rule is to anticipate unexpected actions from other road users and always be in a position to stop if needed. This is a basic principle of defensive driving in Germany and helps prevent accidents in unpredictable situations.