The correct answer is D) Polyester. Polyester has the greatest breaking strength among the synthetic ropes listed. This is due to the inherent properties of polyester fibers, which are known for their high tensile strength and durability. Polyester ropes are commonly used in various marine applications, including in the U.S. Coast Guard, due to their superior strength and resistance to abrasion, UV exposure, and marine environments. The other options, Polyglycine, Polyethylene, and Polypropylene, while also synthetic ropes, do not possess the same level of breaking strength as polyester. Polyglycine is a less common synthetic fiber, while Polyethylene and Polypropylene, while strong, are generally weaker than polyester in terms of overall breaking strength.