Why should memory and network utilization be used to identify bottlenecks?

[answerhappygod]

Why should memory and network utilization be used to identify bottlenecks?

A. High memory and network utilization of the Delivery Controller can indicate a high volume of user logons, indicating that the server may NOT have sufficient resources to handle the load.
B. High memory and network utilization of the Delivery Controller can indicate that the target device will encounter delays when mounting new vDisks.
C. High memory and network utilization of the Delivery Controller can indicate that a high number of processor-intensive applications are being utilized by the virtual desktop users.
D. High memory and network utilization of the Delivery Controller can indicate the presence of a virus or malware.