What is the correct response if, when reversing a combination vehicle the view to the rear is impeded?

You answered correctly. When reversing a large vehicle or a combination vehicle and your view to the rear is blocked, you must use a person to guide you. However, if you lose sight of the person directing you (for example, if the line-of-sight is broken), you must stop immediately. This rule helps prevent accidents, as reversing such vehicles without clear guidance is dangerous. The other answers are incorrect because a directing person is required whenever your rear view is obstructed, regardless of whether you are on a factory premises or entering a priority road. Always stop if you cannot see your guide while reversing.