For each equivalence relation below, find the requested equivalence class. (a) R = {(1, 1),(1, 2),(2, 1),(2, 2),(3, 3),(4, 4)} on the set {1, 2, 3, 4}. Find [1]. (b) R = {(1, 1),(1, 2),(2, 1),(2, 2),(3, 3),(4, 4)} on the set {1, 2, 3, 4}. Find [4]. (c) R is has-the-same-tens-digit-as on the set {x ∈ Z : 100 < x < 200}. Find [123]. (d) R is has-the-same-parents-as on the set of all human beings. Find [you].