单选题 ______ are designed to manage large bodies of information.
A.I/O ports B.Printers
C.Database system D.Keyboards

【正确答案】 C
【答案解析】题目的大意是:数据库系统被设计用来管理大批量的信息。I/O ports:I/O接口,Printers:打印机,Database system:数据库系统,Keyboards:键盘。