When could a dangerous situation arise here?

Your answer is correct.

Here's why: The cycle path ends here, which means the cyclist will likely move onto the roadway. If you continue driving at the same speed (option 1), a dangerous situation can arise because you may not have enough time to react to the cyclist entering your lane. Also, if the cyclist immediately changes into your lane (option 2), this can cause a conflict or collision if you're not prepared.

Option 3, the cyclist stopping at the end of the cycle path, is less dangerous because they are not suddenly entering your lane or causing unexpected movement.

In German traffic rules, you must always be cautious when a cycle path ends and expect cyclists to merge with motor vehicle traffic. Reducing speed and being prepared to give way is important to avoid accidents.