2.某病人40歲，衰弱，無力；其CBC數據：MCV 67 fL，Hb 11.8 g/dL，Hct 34%，RBC 5.8 ×/L，Hb A 2 4.8%。以鐵劑治療三星期無改善，則最有可能罹患下列何種疾病？ (A)Iron deficiency anemia (B)β-thalassemia trait (C)Hb H disease (D)Anemia of chronic disease