. Consider the following relations: edge (X,Y), red(X,Y), blue(X,Y). You should think of the three relations as representing a graph whose edges are colored red or blue (or no color). Provide safe Datalog rules (with negation if necessary) for the following queries. (a) Find the pairs of nodes X and Y where there is path (a sequence of linked edges) from X to Y. (b) Find the pairs of nodes X and Y where there is path (a sequence of linked edges) of even length from X to Y with alternating red and blue colors.