Which suffix indicates an aircraft with no transponder and does not have DME?

The suffix that indicates an aircraft with no transponder and does not have DME is represented by the letter "N." However, among the options provided, the closest match to this concept is the suffix "D." In ATC terminology, the "D" suffix is used to denote aircraft that do not have specific navigational capabilities, including the absence of a transponder required for surveillance and the Distance Measuring Equipment (DME). This designation is essential for air traffic controllers to understand the capabilities and limitations of the aircraft they are managing, allowing them to provide appropriate instructions and ensure safety in the airspace.

The other suffixes represent different aircraft capabilities: "T" usually indicates a transponder-equipped aircraft, while "Y" and "M" may denote other operational statuses or capabilities that do not align with the description provided in the question. Understanding these suffixes helps ATC personnel make informed decisions regarding aircraft separation, surveillance, and overall traffic management.