Please match the Cisco STP enahancement term to its definition.（）
(1) BPDU guard
(2) PortFast
(3) BackboneFast
(4) Loop guard
(5) Root guard
(a) shuts down a port that receives a BPDU when enabled
(b) cuts convergence time by mas-age for indirect failure
(c) prevents the aliernate or root port from being designated in absence of BPDUs
(d )causes Layer 2 LAN interface access port to immediately enter the forwarding state
(e) helps prevent bridging loops due to jni-directional link failures on point-to-point links