1. an invention that was redesigned to be sold abroad.
C
2. an invention that had an effect on wearable technology today.
B
3. an invention that failed twice before it was removed from the market.
A (Although not explicitly stated as 'twice', the recall and replacement issues imply multiple failures)
4. the fact that the invention was energy efficient, but unattractive.
C
5. the fact that other available products could do more than this gadget.
B
6. people who had their travel plans affected by this invention.
A