单项选择题
THE MAIN LIBRARY HAS FIVE FLOORS OPEN TO THE PUBLIC FOURTH FLOOR: Social Sciences & History. 300 ~399, 650 ~659, 900 ~999. Law books are shelved in a separate area—follow signs for the Law Library. THIRD FLOOR: Humanities. 100 ~ 199, 200 ~ 299, 400 ~ 499, 700 ~ 709 & 800 ~ 899. SECOND FLOOR: Science and Technology. 500 ~ 599, 600 ~ 649 & 660 ~ 699. FIRST FLOOR: Current (unbound) Periodicals. An information point is inside the Periodicals Office. GROUND FLOOR: Reference. General reference books and bibliographies. The Reference Librarians on each floor are available to answer queries during office hours. At other times you can ask at the Issue Desk, on the Ground Floor. Books are shelved according to size: Normal size Large size The shelves are colour coded to help you identify them: RED Large books WHITE Normal size books YELLOW Large periodicals BLUE Normal size periodicals Books returned the previous day may be on the Recent Returns shelves, next to the Reference Librarians’ desks.
If you want to look up a word in a dictionary, which floor would you go to（）
A．Ground floor.
B．First floor.
C．Third floor.
D．Fourth floor.