Which condition is most commonly associated with a deficiency in iron?

Iron-deficiency anemia is the condition most commonly linked to a deficiency in iron. Iron is an essential component of hemoglobin, the protein in red blood cells that carries oxygen throughout the body. When iron levels are insufficient, the body struggles to produce enough healthy red blood cells, leading to a decreased capacity to transport oxygen. This can result in symptoms such as fatigue, weakness, and pale skin, all hallmark signs of iron-deficiency anemia.

The other options, while related to various nutritional deficiencies or health conditions, do not involve iron deficiency itself. For example, vitamin C deficiency leads to scurvy, which is a completely different condition primarily related to vitamin C's role in collagen synthesis and antioxidant protection. Gallbladder disease pertains to issues with bile production and digestion rather than a deficiency in any specific nutrient.