Circuit-level firewalls operate at the Session layer (Layer 5) of the OSI model rather than the Network layer (Layer 3) .

In this step, your main objective is to examine and analyze what has occurred and focus on determining the root cause of the incident.
Recovery is incorrect as recovery is about resuming operations or bringing affected systems back into production
Containment is incorrect as containment is about reducing the potential impact of an incident.
Triage is incorrect as triage is about determining the seriousness of the incident and filtering out false positives
Reference:
Official Guide to the CISSP CBK, pages 700-704

Debugging provides the basis for the programmer to correct the logic errors in a program under development before it goes into production.
Source: Information Systems Audit and Control Association, Certified Information Systems
Auditor 2002 review manual, chapter 6: Business Application System Development,
Acquisition, Implementation and Maintenance (page 298).

EDI makes it more difficult to tie an individual to transactions
since EDI involves computer-to-computer data interchanges and this
makes it more difficult to trace the originator of some transactions.
*Answer "It may be difficult to prove criminal intent" is a valid legal issue since it may be very difficult to prove criminal intent by a person perusing computer files and then causing
damage to the files. The damage may have not been intentional.
*Answer "It may be difficult to obtain a trail of evidence of activities performed on the computer" describes the situation of trying to track activities on a computer where the information is volatile and may have been destroyed.
* In answer "It may be difficult to show causation", common law refers to causation of the criminal act. Causation is particularly difficult to show in instances where
a virus or other malicious code erases itself after causing damage to
vital information.