Which of the following is NOT a Linux distro?

Which of the following is NOT a Linux distro?

• BSD
• Ubuntu
• Mint
• Red Hat 

EXPLANATION

Berkeley Software Distribution (BSD) is a Unix operating system derivative developed and distributed by the Computer Systems Research Group 
(CSRG) of the University of California, Berkeley, from 1977 to 1995. Today the term "BSD" is often used non-specifically to refer to any of the BSD descendants which together form a branch of the family ofUnix-like operating systems. Operating systems derived from the original BSD code remain actively developed and widely used.