Explanation: 2182 kHz (SSB) and VHF-FM Channel 16 are international distress, safety, and calling frequencies. Regulations govern their use to ensure they remain clear for urgent communications. **A) Preliminary call must not exceed 30 seconds.** This rule prevents a station from monopolizing the calling channel, allowing others a chance to transmit and keeping the channel accessible for distress calls. **B) If contact is not made, you must wait at least 2 minutes before repeating the call.** This waiting period minimizes congestion on the calling channel, preventing multiple stations from continually re-calling and ensuring the channel is available for other traffic or distress alerts. **C) Once contact is established, you must switch to a working frequency.** The calling channels are for initial contact only. Extended conversations would tie up these vital frequencies, making them unavailable for new calls, safety messages, or distress communications. Therefore, all subsequent communication must move to an appropriate working channel. Since all three statements (A, B, and C) are mandatory regulations for operating on 2182 kHz and Channel 16, **D) All of these** is the correct answer.