Scenario C) What if they both were licensed to carry, The anti gun folks will say there is a problem with the approval process.
They probably were. If you go to the linked article, it has a link to an update. There it is revealed the husband was the shooter, and also that the husband was a Dept. of Corrections employee, and in most states he would have been licensed to carry by default.
It is also said they had been separated and she was seeking a protection order against him (which would have, under Lautenberg, revoked his ability to carry a weapon).
So, how about scenario D? Say, he knew or believed he was about to ruined professionally (most recently in probation/parole, earlier in prisons), and brought his revenge in the form of a final act.
One thing is sure, there's plenty of bitter irony to go around in this story as it unfolds.