Option 3 would have resulted in millions of Japanese starving to death. Their distribution system was demolished. As it was, tens of thousands of Japanese died of starvation that winter, and that was with massive US food aid.
Put into orbit a roll of Kevlar that unspools to be a thin sheet 20 meters long by a few kilomiters from top to bottom. Solar panels on top and a conductive loop around the perimeter so it can use the Earth's magnetic field to maintain orbit (or go into higher/lower orbits to avoid working satellites).
Put it in a retrograde equatorial orbit with its surface plane parallel to its direction of movement to minimize drag. Any bits of debris that hit it will probably have a velocity vector such that all the collision debris will quickly fall out of orbit.
I took a class in neural networks almost 20 years ago. One project was to get a small network to "learn" how to recugnize handwritten numbers. On a 486/33 running overnight it got to the point where it could recognize a number right over 90% of the time, just with a a few dozen neurons. However, it would probably be impossible to determine *why* that network was able to recognize the numbers.
Consciousness (however you want to define it) is almost certainly an emergent property, and if it can emerge in a toddler it should be able to emerge in a properly designed piece of hardware. And even you can you can do a core dump on that hardware, you'll *never* figure out why it's conscious.
Breadth-first search is the bulldozer of science. -- Randy Goebel