If the command arp -f is run, which file will be read by default?

A.
/etc/hosts

B.
/etc/ethers

C.
/etc/arp.conf

D.
/etc/networks

E.
/var/cache/arp

Explanation:

from the man pages:
arp – manipulate the system ARP cache
-f filename, –file filename
Similar to the -s option, only this time the address info is taken from file filename. This can be used
if ARP entries for a lot of hosts have to be set up. The name of the data file is very often
/etc/ethers, but this is not official. If no filename is specified /etc/ethers is used as default.