Mr Wang, a 26 year-old man, was admitted to hospital with pneumonia and had been treated with antibiotics. His temperature has been kept at 39-40 °C for one week, and the fluctuation range of 24 hours has not exceeded 1 °C , which type of fever did it belong to ( ) A. Continued fever B. Remittent fever C. Intermittent heat D. Drug fever E. Irregularly fever