Final answer:
Maintaining professional confidentiality as a prima facie duty means it is a presumptive duty that holds unless overridden by stronger moral obligations in specific circumstances.
Step-by-step explanation:
When we say that maintaining professional confidentiality is a prima facie duty, we mean that it is a duty that appears to be mandatory at first glance, but can be overridden by more compelling moral obligations under certain circumstances. Hence, the correct answer to the question is D) It is a presumptive duty that is binding unless other factors outweigh it in a particular situation. This concept was detailed by Sir William David Ross, who argued that our moral responsibilities are not absolute but are prima facie; they are binding until a more pressing moral duty arises.
Ross acknowledged that conflicts between prima facie duties could occur, and in such cases, we must use judgment based on the specific facts of the situation to determine our actual duty. For example, the duty to keep a promise to a friend may be overridden by the urgent need to help a coworker experiencing a medical emergency.