Correct Option: C

Anemia is a decrease in number of red blood cells (RBCs) or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin deficiency. Because hemoglobin (found inside RBCs) normally carries oxygen from the lungs to the capillaries, anemia leads to hypoxia (lack of oxygen) in organs. Megaloblastic anemia, the most common cause of macrocytic anemia, is due to a deficiency of either vitamin B₁₂, folic acid, or both. Deficiency in folate and/or vitamin B₁₂ can be due either to inadequate intake or insufficient absorption.