What should you do if, during the air brake check, one trailer's spring brakes apply on their own before you've released the parking brake?

Pick an answer

1. Ignore it as long as the other trailers behave normally
2. Continue the trip since spring brakes applying early is a sign the system has extra built-in safety that doesn't need to be looked into
3. Treat it as a possible air system fault at that trailer and investigate before driving, rather than assuming it's normal
4. Disconnect that trailer immediately without checking anything else first

Correct!

Not quite. The correct answer is highlighted.