Which of the following restrictions apply when appending a self-assigned call sign indicator?
A. It must be more than three letters and less than five letters
B. It must be less than five letters
C. It must start with the letters AA through AL, K, N, or W and be not less than two characters or more than five characters in length
D. It must not conflict with any other indicator specified by the FCC rules or with any call sign prefix assigned to another country