Let A= {3,5,7}, B = {21, 30, 35}, and C = {-9, 3, 7}. Definer to be the relation from A to B defined by the following: rry if and only xly. Also, let s be the relation from B to C given by s = {(30,3), (30,-9), (21,3), (35,7)}. (Enter each answer below as a list of ordered pairs separated by commas. Be sure to not repeat any ordered pairs! (a) Find all the elements in r. Answer: r = { 4. } (b) Find all of the elements in the composition rs.