Which layer of the dermis is located below the papillary layer and is responsible for supplying nutrients and oxygen to the skin?

The reticular layer of the dermis is indeed the correct choice because it plays a crucial role in supplying nutrients and oxygen to the skin. This deeper layer is composed of dense irregular connective tissue, which contains a network of blood vessels that deliver essential nutrients and oxygen to the skin's upper layers, including the epidermis.

Additionally, the reticular layer contributes to the skin's strength and elasticity due to its collagen and elastin fibers. It also houses vital structures such as hair follicles, sweat glands, and sebaceous glands, which are important for skin function and health.

The other layers and structures mentioned do not fulfill the role of nutrient and oxygen supply as directly as the reticular layer. The papillary layer, located above the reticular layer, has a more superficial role, primarily focusing on providing a greater surface area for exchange but does not supply nutrients directly to the deeper structures. Subcutaneous tissue, while important for insulation and cushioning, is not part of the dermis and is not directly responsible for supplying the skin. Lastly, sebaceous glands are responsible for producing oils, which help to keep the skin moisturized, but they do not supply oxygen or nutrients to the skin itself.