In Order to Prevent All Anonymous FTP Users from Listing

In order to prevent all anonymous FTP users from listing uploaded file names, what security precaution can be taken when creating an upload directory?

A) The directory must not have the execute permission set.
B) The directory must not have the read permission set.
C) The directory must not have the read or execute permission set.
D) The directory must not have the write permission set.
E) The directory must not contain other directories.