Which type of fiber-optic cable offers stable transport characteristics and enhanced protection against bending?

The correct answer is loose-tube cable. This type of fiber-optic cable is designed to provide stability in transport characteristics due to its construction. The fibers are housed in a tube that allows for some movement within the outer envelope, which helps to reduce stress on the fibers caused by environmental factors like temperature changes and bending.

Additionally, loose-tube cables are often filled with a gel or water-blocking material that protects the fibers from moisture and physical damage. This added layer of protection enhances their durability, making them suitable for outdoor installations where bending and environmental stresses can be a concern.

While ribbon cable is efficient for high-density applications, it is not specifically optimized for bending. Armored cable does provide robust physical protection, which helps against external damage, but does not inherently enhance bending characteristics. Plenum-rated cable focuses on low smoke and flammability for indoor use, which is a different aspect of cable design altogether, not related to transport stability or bending protection.