The trade-off the business must make in this scenario is primarily related to the opportunity cost associated with reallocating production resources from tables to benches.
Given the context, the most relevant response would be:
the difference between the profit of 10 benches and the profit of 15 benches.
This is because the business is increasing the production of benches from 10 to 15, which means they will be producing 5 fewer tables (going from 20 to 15). The trade-off analysis focuses on the additional profit (or potentially lost profit) from producing those 5 additional benches compared to the profit from the 5 tables that will no longer be produced.