Explanation: Routine calls, when made via Digital Selective Calling (DSC), are initiated by interacting with the radio's interface. Modern marine VHF radios equipped with DSC are microprocessor-controlled and require users to navigate through menus and make specific selections to format a call. This includes choosing the type of call (e.g., routine), entering the recipient's Maritime Mobile Service Identity (MMSI), and sometimes specifying a working channel for follow-up voice communication. Option A is incorrect because a "Distress Hot Key" is exclusively for initiating a Distress Alert, which is the highest priority call and distinct from a routine call. Option C is generally incorrect as there isn't a standard "Alarm" button for initiating routine DSC calls; routine calls are made through menu selections. Option D is incorrect because Channel 70 is the *dedicated* DSC channel used for initiating *all* types of DSC calls, including routine priority calls.