Given two relations: STUDENT(S#, D#, Age, Address). DEPT(D#, Name, Chair, Building), ' consider the following query optimization issue. Assume that 25% of students are over 30 years old and that there is one department with name 'CIS'. For the following two equivalent queries: sigma_STUDENT Age > 30 AND DEPT Name = CIS^(STUDENT_STUDENT D DEPT D#)^DEPT) (sigma_STUDENT Age > 30^(STUDENT))_STUDENT D DEPT D#)^(sigma_DEPT NAME CIS^(DEPT)) which one is usually more efficient? Why? Give an example of anomalies caused by uncontrolled concurrent transactions (show your transaction schedule)