Explanation: Coast stations providing public radiotelephony services monitor specific "working" frequencies for ships to initiate routine calls. These frequencies are often published or advertised by the coast station. Initiating a call on the appropriate ship-to-shore working frequency ensures the call reaches the intended station efficiently, as this is where they expect and actively listen for non-distress traffic. Frequencies like 2182 kHz (HF) and Ch-16 (VHF) are international distress and general calling channels. While they can be used for initial contact, their primary purpose is distress, urgency, safety, and initial contact for non-distress communications, followed by a shift to a working channel. Using these critical channels for routine calls to a specific coast station when its designated working frequency is known would unnecessarily tie them up and is not considered the "normal" procedure for initiating routine radiotelephony. Random vacant channels (A) are not monitored, and "any calling frequency" (C) is too broad and inefficient.