The correct answer is D) braided inner layer(s). The braided inner layer(s) of a hydraulic hose determine its overall strength and ability to withstand the high pressures and forces encountered in hydraulic systems. This reinforcing layer, typically made of high-strength materials like steel or synthetic fibers, provides the necessary tensile strength to prevent the hose from bursting or failing under pressure. The inner tube and outer cover serve different functions, such as sealing and protecting the hose, but do not directly contribute to the overall strength as much as the braided inner layer(s). The other options, A) inner tube, B) outer cover, and C) outer armor, are not the primary determinants of the hose's strength, as they have different roles in the hose's construction and performance.