What should a pilot do when a clearance appears to contradict a regulation?

Answer: B — Request clarification from ATC.

When a pilot encounters a clearance that seems to contradict an established regulation, the appropriate course of action is to request clarification from Air Traffic Control (ATC). This step is vital for a safe flying environment, as it ensures that any potential misunderstandings are addressed and resolved before the pilot acts on the clearance. By seeking clarification, the pilot demonstrates professionalism and a commitment to safety. It acknowledges the complexity of air traffic management and ensures that both the pilot and ATC are on the same page. This communication is crucial in maintaining safety in crowded airspace and minimizing the risk of incidents or violations. In contrast, simply reading back the clearance or ignoring it could lead to further confusion or unsafe situations, while rejecting the clearance without understanding the rationale behind it does not contribute to a solution and may disrupt air traffic operations. Therefore, actively communicating with ATC is the most responsible and effective way for a pilot to handle such situations.