【名词&注释】
消化道(digestive tract)、细菌性痢疾(bacillary dysentery)、直肠癌(rectal cancer)、肛门外括约肌(external anal sphincter)、肛门内括约肌(internal anal sphincter)
[单选题]患者主诉粪便呈柏油样,应首先考虑()
A. A.痔疮出血 B. B.结肠肿瘤 C. C.消化道出血 D. D.直肠癌 E. E.细菌性痢疾