Your network contains an FTP server named Server1.
Server1 has an FTP site named FTP1.
You need to hide all of the files in FTP1 that have an .exe file extension.
The solution must ensure that users can list other files in FTP1.
What should you modify?

A.
the FTP authorization rules

B.
the FTP directory browsing

C.
the FTP request filtering

D.
the NTFS permissions

Explanation:
Use the FTP Request Filtering feature page to define the request filtering settings for your FTP site. FTP request filtering is a security feature that allows Internet service providers (ISPs) and Application service providers to restrict protocol and content behavior. For example, using the File Name Extensions tab you can specify a list of file name extensions that are allowed or denied.
Source: http://technet.microsoft.com/en-us/library/dd851560.aspx