Which character(s) must follow most command codes to a coast station using ATOR?

Correct Answer: Option A — +

In ATOR (Automatic Telex Over Radio) and SITOR protocols, the plus sign (+) acts as a command terminator. It informs the coast station's processor that the preceding characters constitute a specific instruction or command code, allowing the system to parse and execute the request correctly without ambiguity during the data exchange.