Which dangerous defects can have occurred on a trailer with overrun brakes which has been parked for some time?

The combination you selected correctly identifies the potential dangers associated with a trailer with overrun brakes that has been parked for some time.

1. **Brakes may not work because of rust**: This is critical because over time, moisture can lead to rust on the brake components, reducing their effectiveness. According to German traffic regulations, vehicles must have functioning brakes to ensure safety.

2. **Cable connections can be defective**: Over time, cables can deteriorate or become damaged, leading to malfunctioning brake systems. This is vital as proper functioning of electrical connections for braking systems is mandated by traffic safety laws.

The third option, regarding tire pressure increasing due to sun exposure, while a concern for vehicle safety, does not directly relate to the critical brake functions of a trailer. Therefore, understanding why the first two options are chosen is essential, as they directly impact the functionality and safety of the trailer on the road.