The most likely option is not even in the list. Our newest super secret super weapon. I put the odds of that at 75%+. Stealth is old tech. Mach 20+ is where it is at. Who cares if they can see you if you are traveling faster than lasers can be swiveled to try and take you out. It is not even our most lethal secret super weapon. Rods from God. Google it.
However, that hypothesis doesn't begin to account for all the data points, puzzle pieces.