How does the Address Resolution Protocol (ARP) work?

A.
It sends a request packet to all the network elements, asking for the MAC address from a specific IP.

B.
It sends a reply packet to all the network elements, asking for the MAC address from a specific IP.

C.
It sends a reply packet for a specific IP, asking for the MAC address.

D.
It sends a request packet to all the network elements, asking for the domain name from a specific IP.

Explanation:
When an incoming packet destined for a host machine on a particular local area network arrives at a gateway,
the gateway asks the ARP program to find a physical host or MAC address that matches the IP address. The
ARP program looks in the ARP cache and, if it finds the address, provides it so that the packet can be
converted to the right packet length and format and sent to the machine. If no entry is found for the IP address,
ARP broadcasts a request packet in a special format to all the machines on the LAN to see if one machine
knows that it has that IP address associated with it. A machine that recognizes the IP address as its own
returns a reply so indicating. ARP updates the ARP cache for future reference and then sends the packet to the
MAC address that replied.
http://searchnetworking.techtarget.com/definition/Address-Resolution-Protocol-ARP