[" 42.Let "R={(3,3),(6,6),(9,9),(12,12),(6,12),(3,9),/_F_(U)],[(3,12),(3,6)}" be a relation on the set "A={3,6,9,12}.],[" The relation is "],[" (a) an equivalence relation "],[" (b) reflexive and symmetric only "],[" (c) teflexive and transitive only "],[" (d) reflexive only "]