Which of the following is a way to reduce costs and strive to achieve a competitive advantage based on lower overall costs per pair sold than rival companies?a. Building production plants in all four geographic regionsb. investing in one or more plant upgrades that have the effect of lowering manufacturing costs per pair producedc. avoiding the use of overtime at the company’s plantsd. avoiding producing private-label shoese. keeping advertising costs in each geographic region to amounts that are below the industry average in that region