This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
[{'content': 'Diphyllobothrium latum causes anemia by: \nSelect and explain. \nA. Its blood sucking activities, B. The Production Of A Toxin That Affects Hematopoiesis, C. Competition with the host for vitamin B12, D. Occlusion of the common bile duct', 'role': 'user'}, {'content': "Answer: C \nExplanation: Diphyllobothrium latum, also known as the fish or broad tapeworm, is the biggest worm and can reach 10 m in size. Humans acquire the infection by eating raw fish containing the larvae of the tapeworm. The worm attaches to the small intestine and causes abdominal discomfo. Nausea, diarrhea, weight loss, and pernicious anemia can result. The anemia is induced by the tapeworm's tendency to compete with humans for vitamin B12, which it easily accumulates from the intestinal contents. Ref: Levinson W. (2012). Chapter 54. Cestodes. In W. Levinson (Ed), Review of Medical Microbiology & Immunology, 12e.", 'role': 'assistant'}]