Which of the metabolites is common in respiration mediated breakdown of fats, carbohydrates and proteins?

Acetyl coenzyme A or acetyl Co-A forms an integral part of cellular process. It provides carbon atoms within the acetyl group to the citric acid cycle (Krebs cycle) to be oxidized for energy production. Acetyl Co-A is produced during breakdown of carbohydrates through glycolysis as well as fatty acid oxidation and enters the citric acid cycle. During gluconeogenesis, protein's carbon skeletons are degraded to acetyl Co-A or acetoacetate which then enter into citric acid cycle. So, acetyl co-A is common in metabolism of carbohydrates, proteins and lipids. So, the correct answer is option B.