Some b-vitamins act as coenzymes during the metabolism of protein, fat, and carbohydrates for energy fill in the blank about coenzymes. the b-vitamin is part of two coenzymes that break down glucose, fatty acids, and amino acids.
a. folate
b. thiamin.
c. iodine
d. riboflavin

B) thiamin

Explanation:

Thiamine (vitamin B1) acts on carbohydrate, fat and protein metabolism, acting as a coenzyme - thiamine diphosphate.  This , in combination with phosphorus, forms coenzyme thiamine pyrophosphate (TPP), which is the key to various reactions such as the transformation of glucose into energy (ATP). TPP acts as a coenzyme in the oxidative decarboxylation of pyruvate, forming acetate and acetyl coenzyme A that is required for carbohydrate, fat and protein metabolism.