A.Backbonefast

B.BPDUfilter

C.BPDUguard
PortFast
Spanning Tree Portfast causes layer 2 switch interfaces to enter forwarding state immediately, bypassing the listening and learning states. It should be used on ports connected directly to end hosts like servers or workstations. Note: If portfast isn't enabled, DHCP timeouts can occur while STP converges, causing more problems.
https://skminhaj.wordpress.com/2015/03/04/spanning-tree-stp-rstp-mst-enhancements/

D.PortFast

A.The EIGRP neighbor relationship was no formed due the IP address being misconfigured between the R2 and R3 interfaces

B.The tunnel source loopback0 interface is not advertised into EIGRP in Branch1.

C.The EIGRP neighbor relationship was not formed due to EIGRP packets blocked by inbound ACL on R3

D.The tunnel source loopback0 interface is not advertised into EIGRP in R3

A.The spanning-tree mode is Rapid PVST+

B.The spanning-tree mode is PVST+

C.The designated port is FastEthernet 2/1

D.The root port is FastEthernet 2/1

E.This is a root bridge

A.It load-balances Layer 2 traffic along the path by flooding traffic out all interfaces configured with the same VLAN.

B.It forwards multiple packets to the same destination over different routed links n the data path

C.It load-balances traffic by assigning the same metric value to more than one route to the same destination m the IP routing table.

D.It uses a shared virtual IMC and a virtual IP address to a group of routers that serve as the default gateway for hosts on a LAN