Answer:
C) Fat metabolism when glucose is unavailable.
Explanation:
Ketones or ketone bodies are byproducts of the oxidation of fatty acids in the liver.
The main source of energy for the body is glucose but when there isn't enough glucose for the body to generate energy from, which might occur as a result of starvation, fasting, unavailability of enough insulin or insulin resistance, the body turns to another source of energy which is fats.
The liver oxidizes these fats or fatty acids to produce ketone bodies which are utilized by the muscles and other organs to produce fuel.
The process which ketone bodies are produced in the liver is known as ketogenesis and it involves the cleavage of acetyl-coA and other biochemical steps.
There are three ketone bodies which are:
Acetone.
Acetoacetate and
Beta-hydroxybutyrate.