The correct answer is C: Spell the words using a standard phonetic alphabet. When voice messages contain unusual words (like names, technical terms, or words that might be misunderstood), you should spell them using a standard phonetic alphabet (Alpha, Bravo, Charlie, Delta, etc.) to ensure they're received correctly. The phonetic alphabet provides clear, unambiguous representations of letters that sound similar when spoken normally (like 'B' and 'D', or 'M' and 'N'). By spelling unusual words phonetically, you ensure the receiving operator can accurately write down the message. This is standard practice in amateur radio message handling and is especially important for formal traffic.