What is the proper format for the inverse DNS mapping for the following address:.198.133.219.25?

What is the proper format for the inverse DNS mapping for the following address:
198.133.219.25?

A.
198.133.219.25.in-addr.arpa.

B.
198.133.219.0.in-addr.arpa.

C.
0.219.133.198.in-addr.arpa.

D.
25.219.133.198.in-addr.arpa.

E.
198.133.25.219.in-addr.arpa.