Suppose that the relations R, S and T have r tuples, s tuples and t tuples, respectively. Derive the minimum and maximum numbers of tuples that the results of the following expressions can have: i. R UNION (S INTERSECT T). ii. SEL[c] (R x S), for some condition c. ii. PROJ[a] (R) - PROJ[a] (R JOIN S), for some list of attributes a