Final answer:
A float plan should be left with friends or family before getting underway, as they are most likely to ensure its proper use in case of an emergency. They will notice your absence and are best able to take immediate actions.
Step-by-step explanation:
Before getting underway, it is critical to leave a float plan with someone who can act in case of an emergency. While notifying local authorities or the Coast Guard is not typically necessary unless the outing is especially risky, the most advisable option is to leave the float plan with C) Friends or family. These are the people who are most likely to notice your absence quickly and take immediate action.
Additionally, marina staff can be helpful, especially if they are familiar with your schedule and habits. However, reliable friends or family members who understand the importance of the float plan will more likely have a vested interest in your safety. A float plan typically includes details such as the names and contact information of all passengers, boat type and registration, trip itinerary, and expected return time.