UPDATE: BPS Pro 13.3+ and BPS free 2.4+ versions have a malware scanner > BPS MScan Malware Scanner
Yeah wouldn’t that be great if it was possible to completely cleanup a hacked website and/or hosting account with a plugin. Unfortunately, it is not possible to completely cleanup a hacked website and/or hosting account using any plugin. There are several WordPress plugins that will find obvious hacker code and files, but it is just not possible to find all hacker files and code with a plugin. See this forum topic link below for more in depth explanation and the steps you can take to cleanup the hacked website and hosting account manually. To answer Question B: “(b) prevents future hacks.” BPS Pro has a perfect track record of protecting websites after 4+ years.
http://forum.ait-pro.com/forums/topic/wordpress-hacked-wordpress-hack-cleanup-wordpress-hack-repair/