The required portable radio apparatus on an international voyage must be stowed in __________.

Correct Answer: Option D — the radio room, bridge, or protected location

46 CFR 109.213 and SOLAS requirements dictate that portable radio apparatus must be stowed in the radio room, on the bridge, or in another protected location. This ensures the equipment is readily accessible to the Master or designated personnel for immediate use during an emergency to facilitate distress communications.