If the Watch Officer hears "PAN PAN" spoken 3 times it means:

Correct Answer: Option B — The station is preparing to transmit an Urgency message possibly concerning the safety of a mobile unit or person.

Hearing 'PAN PAN' spoken three times indicates that the transmitting station is about to broadcast an urgent message. This signal alerts all listening stations that the following communication concerns the safety of a mobile unit or person, requiring them to monitor the frequency and avoid causing any interference.