13 Given the relation EXAM (P, Q, R, S, T, W) and the following set of functional dependencies. FDs: P--> Q Q R S T --> R S --> P Which of the following statements is correct? Select all that apply 09 (2 points) PTW is a candidate key of relation EXAM STW is a candidate key of relation EXAM PTO a candidate key of EXAM No candidate keys in trus relation