You have gained physical access to a Windows 2008 R2 server which has an accessible disc drive. When you attempt to boot the server and log in, you are unable to guess the password. In your toolkit, y

John the Ripper is a password cracking tool that attempts to guess passwords from hashes, but it does not directly reset passwords or activate accounts within the Windows SAM database.

SET (Social-Engineer Toolkit) is a framework for social engineering attacks, not a direct password reset utility for physically accessing and modifying a Windows system's SAM file.

`CHNTPW` (Change NT Password) is a widely recognized Linux utility that can be run from a LiveCD to directly access and modify the Windows Security Account Manager (SAM) database. It allows an attacker or administrator to reset passwords for local Windows accounts and activate disabled user accounts without knowing the current credentials.

Cain & Abel is a Windows-based password recovery and network sniffing tool, and thus cannot be used from a Linux LiveCD as specified in the question.