Refer to the exhibit:

When PC1 sends an ARP request for the MAC address of PC2, network performance slows dramatically, and the switches detect an unusually high number of broadcast frames. What is the most likely cause of this?

A.
The portfast feature is not enabled on all switch ports.

B.
The PCs are in two different VLANs.

C.
Spanning Tree Protocol is not running on the switches.

D.
PC2 is down and is not able to respond to the request.

E.
The VTP versions running on the two switches do not match.