The only key to solve this question is the sentence "everyone would want to buy a new, improved keyboard.".
If I need to weaken it, I can say some do not want the improvement.
This is what option B is doing.
Americans do not want the improvement, hence conclusion is weakened.
If I need to weaken it, I can say some do not want the improvement.
This is what option B is doing.
Americans do not want the improvement, hence conclusion is weakened.

.jpg)








