What Is the Meaning of the Term "Protein-Sparing

What is the meaning of the term "protein-sparing"?

A) If there is not enough protein in the diet, the body cannot digest starch.
B) If the diet provides enough carbohydrates and fats for energy, protein can be used to make new proteins.
C) Fiber is needed in order to absorb amino acids into the body.
D) If the diet provides enough protein, glucose will be used for energy.
E) Protein deficiencies will cause the breakdown of muscle.