Map Parallels shared folder to drive letter
CentOS (like all Linux distros) doesn't have "drive letters" - that is a throwback to the toy operating systems that were installed on some computers in the 1990's and early this century. I believe they went by the name "Windows".

Instead it uses mount points.

Once you have installed the Parallels tools you can use the "Shared Folders Tool" to specify the mount point for the folders that are being shared from your Mac.