This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Pathology
[{'content': 'Which of the following statements is true \nSelect and explain. \nA. Chronic myeloid leukemia occurs beyond 50 years of age, B. Hairy cell leukemia in less than 50 years has a good prognosis, C. Acute lymphoid leukemia in less than 1 year has a poor prognosis, D. Chronic lymphocytic leukemia occurs in less than 50 years of age', 'role': 'user'}, {'content': 'Answer: C \nExplanation: There are 4 main types of leukemia, based on whether they are acute or chronic, and myeloid or lymphocytic: Acute myeloid (or myelogenous) leukemia(AML) Chronic myeloid (or myelogenous) leukemia(CML) Acute lymphocytic (or lymphoblastic) leukemia (ALL) Chronic lymphocytic leukemia (CLL)', 'role': 'assistant'}]