Using the following relations: relation s A B C 1 1 2 1 2 3 2 1 1 relation t B C D 1 2 1 2 1 2 3 3 2 Compute the result of each relational algebra expression below. Don't forget to label each column in the result with the appropriate attribute name. a. (project[AC](s)) |x| (project[BD](t)) b. s |x| (rename[D<-A](project[D](s |x| t))) c. ((project[AB](s)) |x| (project[BC](t))) - s