The correct option is C Vitamins
In animals fats, carbohydrates and proteins are responsible for generation of energy.
Proteins are metabolized by breaking down into individual amino acids by various enzymes and hydrochloric acid present in the gastro-intestinal tract which are further broken down to α-keto acids which can be recycled in the body for generation of energy, and production of glucose or fat or other amino acids.
Fats are the major contributor of the molicules like acetyl-CoA which is an integral part of Krebs cycle and generates energy.
Carbohydrates takes part in cellular process like glycolysis and leads to generation of energy.
Vitamins are not directly involved in generation of energy although they indirectly support the process of energy production.
So, the correct answer is option C.