Avidin, a protein in egg whites, binds biotin very tightly and prevents its absorption in the intestine. Consumption of large amounts of raw eggs can result in a biotin deficiency. Which of the following metabolic conversions cannot occur without biotin? (Note: This is not a problem with cooked eggs because cooking denatures avidin.)

a. Pyruvate oxaloacetate

b. Phosphoenolpyruvate 2-phosphoglycerate

c. 1,3-Bisphosphoglycerate glyceraldehyde-3-phosphate

d. Fructose-1,6-bisphosphate fructose-6-phosphate