A company is experiencing network delays. The network administrator discovers that a worker in a location far from the MDF has connected an old 10BASE-T switch with redundant links to the existing network. How could this action be responsible for the impaired network performance?（）

A.Connecting a host to the old switch has created a broadcast storm.

B.The 10BASE-T switch forced the entire network to be reduced to 10 Mbps operation.

C.The old switch does not support VLANs, which has disabled the VLAN configuration of the entire the network.

D.The old switch does not support full-duplex operation, effectively forcing half-duplex operation throughout the network.

E.Spanning Tree Protocol has elected the old switch as the root bridge, creating inefficient data paths through the switched network.