The beans used for producing decaffeinated coffee do not cost much more before processing than the beans used
Why this is right
This also has the appealing "ruling out not", so it's ripe for negating. If we say, "Yo, author -- the beans they use for decaff do cost much more even before processing than the beans used for producing regular coffee", then we can argue that decaff coffee does cost way more to provide to the consumer, and thus that the price difference can be accounted fo by the greater cost of providing decaff. Again, the author's argument was a Part vs. Whole type of move. She thought that if the process of removing the caffeine wasn't adding a lost of cost, then the cost of providing decaff overall wouldn't be much more costly. In doing so, she failed to consider that there could be other facets of providing decaff to consumers that are much more expensive than providing regular coffee to consumers. She assumed that shipping decaff does not cost much more. She assumed that grinding and brewing decaff does not cost much more. And, as this answer is saying, she assumed that the beans themselves do not cost much more. Put another way, someone could have objected to the original argument by saying, "Decaff absolutely has a higher retail price because of its higher productions costs. Yes, the process of removing caffeine doesn't cost much, but you have to find special beans with tons of robust flavor so that when you remove the caffeine there's still a lot of rich coffee flavor. Those premium beans are very expensive."
Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.