This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Pharmacology
[{'content': 'Define sustained fever? \nSelect and explain. \nA. Fever is persistent and does not vary by more than 0.5degC/day, B. Fever is persistent and varies by more than 0.5degC/day., C. Fever is persistent and does not vary by more than 1degC/day, D. fever is persistent and varies by more than 1degC/day.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Sustained fever is persistent and does not vary by more than 0.5degC (0.9degF)/day. Remittent fever is persistent and varies by more than 0.5degC (0.9degF)/day. Relapsing fever is characterized by febrile periods that are separated by intervals of normal temperature; teian fever occurs on the 1st and 3rd days (malaria caused by Plasmodium vivax), and quaan fever occurs on the 1st and 4th days (malaria caused by Plasmodium malariae).Ref: Nelson; 20th edition; Chapter 176; Fever; Page no: 1278', 'role': 'assistant'}]