Which letter corresponds to the phonetic sound "Zulu"?

The correct answer is Z. In the context of international phonetic alphabets used in radio communications, including the NATO phonetic alphabet, each letter is assigned a specific phonetic name to ensure clarity over voice communication. The letter "Z" is represented by the word "Zulu" when communicating, which helps to avoid misunderstandings due to similar-sounding letters.

Using "Zulu" as the phonetic representation of "Z" is particularly useful in aviation, maritime, and other professional communications where clear and precise communication is essential. The system aims to provide a standardized way to transmit letters, especially in noisy environments where voice clarity may be compromised.