Each interface has its own MAC address??

[vivek198]

So, we all know that a router can have 1 or even up to 8 IP addresses assigned to an interface, but I would like to draw your attention to page 340-341 of CCNA study guide, the answer to the first question says "Lab_B router will respond with the MAC address of the FA0/0 interface" giving the impression that the router has more than one MAC address... so I am confused here, and I done some research online and found a post elsewhere that says "I did an ARP request on network, and the router responded with 3 MAC addresses??"

So isn't a device supposed to have 1 and only 1 unique HW address??