This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: parasitology, Subject name: Microbiology
[{'content': 'true about Giardiasis - \nSelect and explain. \nA. Only cyst is infective, B. Reside in ceacum, C. Only man to man transmission, D. Exist in one phases', 'role': 'user'}, {'content': 'Answer: A \nExplanation: During unorable conditions in the duodenum enchantment occurs .usually in the colon .Infection of man occurs by ingestion of cyst in contaminated food and water .Infective dose is 10 to 100 cysts (refer pgno:31 baveja 3 rd edition)', 'role': 'assistant'}]