In the MAC address 0000.0c07.ac03, what does the “03” represent?

A.
HSRP router number 3

B.
Type of encapsulation

C.
HSRP group number

D.
VRRP group number

E.
GLBP group number

Explanation:
Each router keeps a unique MAC address for its interface. This MAC address is always
associated with the unique IP address configured on the interface. For the virtual router
address, HSRP defines a special MAC address of the form 0000.0c07.acxx, where xx
represents the HSRP group number as a two-digit hex value. For example, HSRP Group 1
appears as 0000.0c07.ac01, HSRP Group 16 appears as 0000.0c07.ac10.
Reference:
Cisco Hot Standby Router Protocol (HSRP)
(http://tools.ietf.org/html/rfc2281#page-13)