What can the architect conclude?

Refer to the exhibit. A customer needs a wired network upgrade and has complained about performance issues. The architect has collected information about traffic flow on several switch ports in different locations across the network, and the results are shown in the exhibit. Each of these ports is a 1Gbps port.

What can the architect conclude?
A . None of these ports show any periods of congestion.
B . Port 1 shows periods of congestion, other ports are not congested.
C . Port 3 shows periods of congestion, other ports are not congested.
D . All of the ports show serious congestion.

Answer: D