What must you be prepared for in this situation?

You answered correctly by choosing 1 and 2, and here's why:

In this situation, the traffic signs and barriers clearly indicate roadworks. According to German traffic rules, when you see a construction site, you must be prepared for an uneven and potentially dirty roadway because the surface may have loose gravel, dirt, or bumps caused by the construction activity. This can affect your vehicle's stability and braking.

Additionally, workers and construction equipment may be present on or near the roadway. You need to be alert and reduce your speed to ensure safety for both the workers and yourself.

The option about police regulating traffic is not relevant here because there are no signs or signals indicating police presence.

Remember, reducing speed and maintaining caution in construction zones is essential to avoid accidents and ensure smooth traffic flow in Germany.