Definition: In this task, you are given a context and four options. Each option is a suggested ending for the context. You should read the context and pick the best ending for the context. Please answer with "A", "B", "C", and "D".
Input: [header] How to install ahci support for ati sb600 sata controllers on existing windows installations [title] Back up your critical data, and especially your registry. [step] There are lots of programs out there to do it. Hopefully you won't have to use your backup, and the procedure is pretty safe, but consider yourself warned anyway. <sep> (A) Backup your hard drives-those are hard to backup, and the files are not working. Back up your own files-you can still get files for friends and others on your computer, but at 00x128 ng/dw1.01 you just backed down your device. (B) [title] Don't do a virus procedure this time! [step] Erase all your data. Do not attempt to install another version of this computer operating system until you have laid down security guidelines. (C) If any of the programs be corrupt and the hard drive becomes corrupt, then go back to the file it was saved, and delete it. This will destroy usgs download modes etc. (D) [title] Make sure ahci is disabled in the bios. [step] If it's enabled and you can boot into windows, you don't need this walkthrough.
Output:
D