Well... THC is destroyed by light and air's oxygen. So if you find a way to protect the THC from both, it will be very safe.
Ive heard that in the buds the THC is stored into the cells, and when we cook with it the cells are broken and the THC is released. So, i think storing cured bud would be the safest method, as the THC would be double protected, as it would be safely stored into the cells.
Vacuum packing seems a very good way to avoid contact with air... so i would choose the option 3. And store it in a dark and cool place.