Which of the following vitamins is involved in the regulation of homocysteine metabolism through the methionine synthase reaction?

A Vitamin B12 ✓
B Vitamin B6
C Folic acid
D Vitamin E

Explanation

Vitamin B12 plays a crucial role in the regulation of homocysteine metabolism through the methionine synthase reaction, where it acts as a co-factor.

Source

Biochemistry by Stryer
Metabolic and Nutritional Disorders Nutrition and Biochemistry Vitamin Metabolism Hard MEDICAL Confidence: high