Which SELCAL code format is used to alert a specific aircraft on HF or VHF radio?
-
A
A two-letter prefix followed by a four-digit number
-
B
A four-letter code using characters A through S (excluding I, N, O)
-
C
A six-character alphanumeric string assigned by ICAO
-
D
A three-digit octal code broadcast on 121.5 MHz