Which of the following statements is true of business unit strategy? A. It refers to decisions made at the level of the strategic business unit about how to gain and sustain advantage. B. It refers to decisions about how to effectively implement the business unit strategy within functional areas. C. It refers to decisions at the corporate level of organization about how to improve a firm's ability to recruit more resources. D. It refers to decisions that are made by senior corporate executives about what markets to compete in.