Changes in Vitamin B₁₂ Are Most Dramatic in Tissues with the Greatest

Changes in vitamin B₁₂ are most dramatic in tissues with the greatest rate of cell turnover because:

A) Deficiencies result in impaired RNA synthesis in any cell where chromosomal replication and division takes place.
B) Deficiencies result in impaired excretion of metabolic waste products from the cells' cytosol.
C) Deficiencies result in impaired function of cytochrome P450.
D) Deficiencies result in impaired DNA synthesis in any cell where chromosomal replication and division takes place.