Which two of these are used in the selection of a root bridge in a network utilizing Spanning Tree Protocol IEEE 802.1D？（）

A.VTP updates are ignored and forwarded out all ports
B.VTP updates are ignored and forwarded out trunks only
C.VTP updates are made to the VLAN database and are forwarded out trunks only
D.VTP updates are ignored and are not forwarded

A.8192
B.16384
C.49152
D.65535

A.enforce the placement of the root bridge in the network
B.ensure that a port is transitioned to a forwarding state quickly if a BPDU is received
C.enforce the borders of an STP domain
D.ensure that any BPDUs received are forwarded into the STP domain