A customer wants to know what version of DirectX the current workstation has installed. Which of the following command line tools would the customer use?（）

单项选择题Which of the following would BEST optimize a computer that is heavily used? （）

A.Scandisk
B.Defrag
C.Indexing
D.Chkdsk

单项选择题Which of the following BEST describes the purpose of user account control (UAC) in WindowsVista?（）

A. UAC ensures that standard users cannot access the files and folders of administrative users.
B. UAC allows a computer administrator to add new user accounts to the system, configure passwords and settings for existing users, or remove existing user accounts.
C. UAC ensures that viruses and other malware cannot infect the computer, eliminating the need for third-party antivirus solutions.
D. UAC ensures that important changes cannot be made to Windows Vista without the permission of a computer administrator.

单项选择题A Denial of Service (DoS) attack is:（）

A. an attempt to bring down a website or other online service.
B. a prank where someone sends an unauthorized e-mail attempting to close a user’s e-mail account.
C. stealing a user’s identity and making changes to their accounts.
D. an attempt to change a user’s password to prevent access to a service by repeatedly guessing the user’s information.

单项选择题A dry cleaner is having issues with their computer overheating. Which of the following preventive maintenance techniques would be the BEST short-term resolution to the problem?（）

A. Update the firmware on the machine to accommodate for higher temperatures.
B. Use Disk Cleanup and Defrag to keep the machine from working as hard.
C. Use a can of compressed air to clean out blocked ventilation.
D. Relocate the machine to a cooler part of the building.

单项选择题Which of the following connectors is MOST commonly used for UTP cable?（）

A.RJ-45
B.RJ-11
C.LC
D.SC