What is an important step to take when verifying a newly proposed network security solution?

What is an important step to take when verifying a newly proposed network security solution?

A.
Test the design on a pilot network for expected results prior to implementing on the production network.

B.
Run a network audit to determine types of traffic in use on the network.

C.
Launch campus updates into the production network and monitor impact to see if configuration changes are needed.

D.
Create an interruption of data flow to determine test "back-door" access methods.