A 23-year-old, single, unemployed female in her eighth month of pregnancy is seen in a volunteer-staffed obstetrics clinic. Her first child, born at home and exclusively breast-fed, had prolonged diarrhea and died from an intracranial hemorrhage at 1 month of age. To help prevent a similar problem in this pregnancy, the resident gives her a free prescription for a vitamin and advises her to take one 20-mg tablet each day. He also informs her that the infant should receive an injection of this vitamin soon after birth. The vitamin prescribed is most likely to be required as a coenzyme in which of the following enzymes?

1. A)Homocysteine methyltransferase
2. B)γ-Glutamyl carboxylaseGABARITO
3. C)δ-Aminolevulinate synthase
4. D)Glutamic acid decarboxylase
5. E)Prolyl hydroxylase