What effect does the sticky bit have when set on a directory?

A.
There is no effect because the sticky bit has been deprecated in Linux.

B.
It provides a hint to the kernel that files in this directory should be cached in memory, if
possible.

C.
It restricts deletion of files in this directory to only the root user and the file owner regardless of
writepermissions for other users.

D.
It instructs the kernel to keep the underlying data for the files in the directory intact to allow for
undeletionof important files.