Explanation: The international radiotelephony calling and distress frequency in the Medium Frequency (MF) band is 2182 kHz. This frequency is a critical component of the Global Maritime Distress and Safety System (GMDSS) for voice communications, used by ships and coast stations to initiate distress alerts and establish initial contact. * **C) 2182 kHz:** This is the correct, internationally recognized MF radiotelephony distress and calling frequency. * **A) 2670 kHz:** While an MF frequency used in maritime radio, it is typically a working frequency for general ship-to-shore or intership communication, not the primary distress channel. * **B) Ch-06 VHF:** VHF Channel 06 is an intership working frequency, not an MF frequency, and not the primary VHF distress channel (which is Ch-16). * **D) Ch-22 VHF:** VHF Channel 22 is a U.S. Coast Guard liaison channel, not an MF frequency, and not the primary distress channel.