Final answer:
The correct answer is d) LACP. HSRP, GLBP, and VRRP are Cisco-proprietary protocols that elect a master router and a virtual router backup. LACP is not Cisco-proprietary and is used for aggregating multiple physical links into a single logical bundle.
Step-by-step explanation:
The correct answer is d) LACP.
HSRP (Hot Standby Router Protocol), GLBP (Gateway Load Balancing Protocol), and VRRP (Virtual Router Redundancy Protocol) are all Cisco-proprietary protocols that elect a master router and a virtual router backup.
LACP (Link Aggregation Control Protocol) is not Cisco-proprietary. It is a standardized protocol defined in the IEEE 802.3ad standard and is used for aggregating multiple physical links into a single logical bundle, providing increased bandwidth and redundancy.