问题
单项选择题
Password is a secret series of (69) that enables a user to access a file, computer, or program. On multi-user systems, each user must enter his or her password before the computer will respond to (70) . The password helps ensure that (71) users do not access the computer. In addition, data files and programs may require a password.
A．symbol
B．sign
C．characters
D．characteristic
答案
参考答案：D
解析：本题意思为“密码是一组字符串”，characteristic此处意为“字符串”。答案为D。