When considering the use of hard links, what are valid reasons not to use hard links?

A. Hard links are not available on all Linux systems because traditional filesystems, such as ext4, do not support them

B. Each hard link has individual ownership, permissions and ACLs which can lead to unintended disclosure of file content
C. Hard links are specific to one filesystem and cannot point to files on another filesystem
D. If users other than root should be able to create hard links, suln has to be installed and configured
E. When a hard linked file is changed, a copy of the file is created and consumes additional space