10 請由下列數值計算病人 RPI（reticulocyte-producing index）？RBC count: 1.80 × 109/L；Hemoglobin: 5.0 g/dL；Hematocrit: 15%；Reticulocyte count:3%
(A) 0.25%
(B) 1%
(C) 2.5%
(D) 3%