Don't Jack It Up

Which one of the following is an assumption on which the argument depends?

From time to time there is public outcry against predatory pricing - where a company deliberately sells its products at prices low enough to drive its competitors out of business. But this practice clearly should be acceptable, because even after its competitors go out of business, the mere threat of renewed competition will prevent the company from raising its prices to unreasonable levels.

Answer: any pricing practice that does not result in unreasonable prices should be acceptable.