Refer to the exhibit. Why is the Total Active Signatures count zero?

A.
IPS is in fail-closed mode.

B.
IPS is in fail-open mode.

C.
The 128MB.sdf file in flash is corrupted.

D.
IPS has not been enabled on an interface yet.

E.
The flash:/128MB.sdf needs to be merged with the built-in signatures first.