Answer:
The correct answer is: dense irregular connective tissue.
Explanation:
The endoneurium is the innermost layer that wraps the nerves. The other layers are the epineurium and the perineurium.
The endoneurium, also called endoneurial sheath, is composed of dense irregular connective tissue, and covers the myelin sheath of each nerve fiber in the PNS (peripheral nervous system).
Each myelinated fiber with its corresponding endoneurial sheath, is wrapped along other axons inside the perineurium (which surrounds and protects each nerve fascicle).
In cases in which the nerve fascicles are too large, they are also surrounded by another protective layer of connective tissue, the epineurium, which contains blood vessels and fat tissue.