Trader Joe's earns over $$2,000$ of annual sales per square foot$-$nearly double that of Whole Foods. By selling mainly private label goods under its own brand, Trader Joe's keeps its costs low, enabling it to offer lower prices. By being very selective about the particular products that it carries, it has also managed to ensure that its brand is associated with very high quality. What strategy is Trader Joe's using to gain competitive advantage?$-$ focused low$-$cost strategy$-$ broad differentiation strategy$-$ best$-$cost provider strategy$-$ focused differentiation strategy$-$ low$-$cost provider strategy