Which feature should you use to restrict certain actions only to an administrator account on a Windows 7 computer?

Windows Experience Index is a performance rating system for system hardware and software components, not a security feature for restricting actions.

User Account Control (UAC) is a security feature in Windows that helps prevent unauthorized changes to the operating system by prompting users for permission or an administrator password before making changes that require administrative privileges. This mechanism ensures that actions requiring elevated rights are explicitly approved, thereby restricting certain actions to administrator accounts or requiring their consent.

BitLocker is an encryption feature for entire volumes or drives, providing data protection, not access control for specific user actions.

Computer Management is a collection of administrative tools for managing local or remote computers, but it does not inherently restrict actions to administrators; rather, it's a console where administrators perform tasks that might then be subject to UAC.