In FM communications, the information is applied to the carrier by:

Correct Answer: Option B — Varying the frequency of the carrier.

Frequency Modulation (FM) encodes information by varying the instantaneous frequency of the carrier wave while maintaining a constant amplitude. This technique, designated as F3E in maritime radiotelephony, provides superior noise immunity compared to amplitude-based modulation, making it the standard for VHF maritime voice communications within the GMDSS framework.