A user cannot access a company database. The technician has gathered all relevant information, identified the problem, and established a likely theory for the issue. After testing this theory, the technician finds it is incorrect. Which of the following should the technician do NEXT to resolve the problem?

A.
Establish a plan of action.

B.
Ask the user when the problem first started.

C.
Verify system functionality.

D.
Re-establish a new theory.