The Hot Standby Router Protocol (HSRP) uses a virtual MAC address format of 0000.0c07.acXX, where XX is the HSRP group number in hexadecimal. For HSRP group 22, the hexadecimal equivalent is 16, so the default virtual MAC address is 00:00:0c:07:ac:16. However, there seems to be a typographical error in the options provided. The correct answer should be C, which matches the HSRP virtual MAC address format for group 22. References: This information is based on standard HSRP operation as described in Cisco documentation and the Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) study materials.