All client computers on your company network run Windows 7. After the installation of a third-party defragmentation tool

[answerhappygod]

All client computers on your company network run Windows 7.
After the installation of a third-party defragmentation tool, several employees are unable to start their portable computers in normal or safe modes.
The Original Equipment Manufacturer (OEM) recovery partition is not installed on the computers. The Boot Configuration Database (BCD) has also been corrupted.
You need to repair the BCD so that the computers can start.
What should you do?

A. Create a new system repair disc and run the System Image Recovery tool on the employee computers.
B. Create a new system repair disc and run the Startup Repair recovery tool on the employee computers.
C. Start each computer from the installation DVD. Select the Last Known Good Configuration advanced boot option.
D. Start each computer from the installation DVD. In the System Recovery Options dialog box, select the System Restore recovery tool.