Explanations:

Microsoft is not the exploit, but if Microsoft documents how the vulnerability can be used to gain unprivileged access, they are creating the exploit. If they just say that there is a hole in the product, then it is only a vulnerability. The security "hole" in the product is called the "vulnerability". It is documented in a way that shows how to use the vulnerability to gain unprivileged access, and it then becomes an "exploit". In the example given, Windows 2003 Server is the TOE (Target of Evaluation). A TOE is an IT System, product or component that requires security evaluation or is being identified. The hacker that would use this vulnerability is exploiting it, but the hacker is not the exploit. The documented method of how to use the vulnerability to gain unprivileged access is the correct answer.