Below is the output from a troubleshooting activity:
1. SaaS application is unavailable to a set of users at a single site.
2. WAN connectivity was considered to be the cause of the problem.
3. Upon testing, it seemed the WAN connectivity was up, but the default gateway was unreachable from the internal users.
4. The faulty switch was replaced to bring up the connectivity.
5. The incident was documented.
Based on the methodology, which of the following steps was overlooked during the activity?
A. Problem identification
B. Establish theory of probable cause
C. Verify full system functionality
D. Establish a plan of action and implement the solution
