At which traffic level point will you consider purchasing a second Cisco ACE 4710 Appliance?

A single Cisco ACE 4710 Appliance deals with all data center and the data center traffic. At which traffic level point will you consider purchasing a second Cisco ACE 4710 Appliance?

A.
when the L4Perf CPS reaches 20,000

B.
when the L4Perf CPS reaches 100,000

C.
when the L4Perf CPS reaches 80,000

D.
when the L7Perf CPS reaches 40,000