Explanation: When reviewing previously transmitted messages, especially in digital modes or with voice recorders, it's crucial to take steps to prevent accidental re-transmission. Modern transceivers can quickly send stored data or recorded audio. Inadvertently pressing a transmit button (PTT) or operating an input device could send an outdated, incomplete, or unintended message, causing unnecessary interference or transmitting incorrect information. Good operating practice requires vigilance to avoid accidental transmissions. A) Pressing the “Call” key, if applicable, is an operational function for specific features and does not serve as a precaution against accidental transmission. B) Always saving the message is a data management practice, not a safeguard against re-transmitting it inadvertently during review. D) Stating that no precautions are necessary is incorrect. Accidental transmissions are a common operational pitfall that good amateur practice aims to prevent.