The DF-GLS test for a unit root has higher power than the Dickey-Fuller test. Why should you use a more powerful test? O A. A more powerful test improves the analyst's ability to distinguish between a unit AR root and a root less than 1. O B. A more powerful test is more likely to reject the null hypothesis when the null hypothesis is false. O C. A more powerful test is more efficient. O D. Both (a) and (b) are true