Answer:
Option C, thickening and hardening of the outer layer
Explanation:
The medical term "sclerosis" originates from the Greek words "skleros" and "sklerosis," which mean 'hard' and 'hardening', respectively. Because of this, it is often used to describe the thickening and hardening of a tissue layer.
For example, the term arteriosclerosis is defined as the thickening and hardening of the walls of arterial vasculature, usually as a result of fatty deposits developing into plaques that diminish the diameter of the vessel lumen thereby decreasing blood flow through the arteries.
In short, the medical term sclerosis best fits option C.
