Iron Deficiency Anemia

A 52-year-old man with chronic gastrointestinal blood loss presents with microcytic anemia. Regarding the stages and diagnostic criteria of iron deficiency, all of the following are correct EXCEPT:

A 38-year-old woman with chronic menorrhagia presents with microcytic hypochromic anemia. Regarding the morphological and biochemical features of iron deficiency anemia, all of the following are true EXCEPT:

Regarding the pathophysiology and laboratory diagnosis of iron deficiency anemia, all of the following statements are correct EXCEPT:

In iron deficiency anemia, which of the following iron studies findings is EARLIEST to appear?

A 42-year-old woman with iron deficiency anemia (Hb 7.8 g/dL, ferritin 8 ng/mL) secondary to celiac disease presents with severe malabsorption. She has failed oral iron therapy twice due to poor compliance and persistent GI symptoms. What is the drug of choice for iron replacement?