Do you think the cop’s line of questioning is fair? Does he ask leading questions?

The correct answer is option C: both are correct.

Explanation:

Mark's point of view is right. In hazardous material handling, placards should be placed on the outside of a vehicle or container to comply with regulations that state the importance of warning others that a hazmat is inside. They also help to identify what type of dangerous material is it so that people can take specific precautions and follow certain instructions. In additioin, Sarah is also right because, according to international regulations, placards must be placed at least 3 inches away from any other marking. Thus, nothing can affect their visibility.