The exhaust noise has suddenly become unusually loud. What is the right thing to do?

The selected combination is correct because checking the exhaust system for faulty mountings and ensuring that any possible damage is promptly repaired are critical actions you need to take when you notice an unusual increase in exhaust noise. According to German traffic regulations, vehicle owners are responsible for maintaining their vehicles in a roadworthy condition. This includes ensuring that the exhaust system functions properly and complies with noise regulations. Failing to address such issues could lead to fines or implications for vehicle safety. Option 3 is incorrect; exceeding exhaust noise limits is not permitted, and drivers must adhere to the regulations until repairs are made. Thus, the selected combinations prioritize safety and compliance with traffic laws.