Charlis, the CEO of Dickens Inc., has chosen to use the industrial organization (I/O) model of above-average returns for Dickens. Which of the following is an assumption Charlis would make using this model? Any resource differences that develop between firms will be long term. Firms acquire different resources and develop unique capabilities based on how they combine and use the resources. The external environment imposes pressures and constraints that determine the strategies that would result in above-average returns. Firms can earn above-average returns by producing standardized products at costs below those of competitors