Determine whether the relation r defined below is reflexive, irreflexive, symmetric, asymmetric, antisymmetric, or transitive. for each property, either explain why r has that property or give an example showing why it does not. a) let a = {1, 2, 3, 4} and let r = { (2, 3) } b) let a = {1, 2, 3, 4} and let r = { (1, 1), (1, 2), (1, 3), (2, 1), (2, 2), (2, 4), (3, 1), (3, 3), (4, 1), (4, 4) }.