Briefing F5 Knowledge

Which of the following is an example of a sub-zone?

A top-level DNS zone uses a CNAME record to point to a sub-zone. Which of the following is an example of a sub-zone?

A.
www.F5.com/sub

B.
www.F5.com

C.
www.gslb.F5.com

D.
.com

E.
f5.com