What is the proper way to address an officer to show military courtesy?

Addressing an officer as "SIR" or "MA'AM" is the proper way to show military courtesy because it reflects the respect and hierarchy that is inherent in military culture. These terms are universally recognized and indicate recognition of the officer's authority, ensuring that the interaction is respectful and formal.

This form of address is applicable regardless of the officer's specific rank or position, allowing for a consistent and respectful interaction across the different branches of the military. Using "SIR" for male officers and "MA'AM" for female officers is a standard practice, reinforcing the professional decorum expected within the military environment. Such protocol helps to maintain discipline and respect among service members.

The other options do not adequately convey the same level of respect or adherent to military customs. Addressing an officer by their last name only lacks the formal recognition necessary in military interactions. Using their rank solely does not encompass the courtesy required in direct conversation. Likewise, using a full name can come across as overly familiar and not in line with traditional military decorum.