This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Which of the following is FALSE regarding amino acid metabolism? 
Select and explain. 
A. Histamine is a product of decarboxylation of histidine, B. Threonine provides the thioethanol moiety for biosynthesis of coenzyme A, C. Ornithine serves as a precursor of both spermine and spermidine, D. Serotonin and melatonin are metabolites of tryptophan
B: Threonine provides the thioethanol moiety for biosynthesis of coenzyme A
Answer: B: Threonine provides the thioethanol moiety for biosynthesis of coenzyme A 
Explanation: Serine provides the thioethanol moiety of coenzyme A, not Threonine. Because acetyl-CoA has a much higher energy content than acetic acid, it combines readily with substances in reactions that would otherwise require outside energy. Acetyl-CoA is therefore often called "active acetate." Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. (2012). Chapter 1. General Principles & Energy Production in Medical Physiology. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks (Eds), Ganong's Review of Medical Physiology, 24e.