单选题 A newborn with birth weight 3.2 kg. At 48 hours postnatal, serum total bilirubin is 267 μmol/L and unconjugated bilirubin is 249 μmol/L. While awaiting further laboratory results, the initial treatment of choice is:()新生儿出生体重3.2kg,生后48小时血清总胆红素267μmol/L,未结合胆红素249μmol/L.在等待化验检查结果期间,首选的治疗方法是:()