单项选择题
ATM when referring to computers is a dedicated, connection switching technology that organizes digital data into 53-byte (48) units and transmits them over a physical (49) using digital signal technology. ATM is capable oftransniitfing at speeds of 155 or 622 MBit/s and faster.
48（）
A．minuteness
B．toothful
C．cell
D．spot