Final answer:
A Type I PFD, or off-shore life jacket, is the best choice for protection in rough waters where rescue may be delayed as it provides the most buoyancy and is designed to turn unconscious individuals face-up.
Step-by-step explanation:
The type of Personal Flotation Device (PFD) that offers the best protection when boating in rough waters where rescue may take a while is a Type I PFD, also known as an off-shore life jacket. This PFD is designed for rough or remote waters where rescue can be delayed. They provide the most buoyancy, are designed to turn most unconscious individuals to a face-up position in the water, and are highly visible, which is crucial for rescue operations in challenging conditions.