a) Given the set X = {k,1,m,7,8} with topology t = {X,ϕ,{7,8}, {1, m, 7}}. Find int(A), ext(A) and Bd(A) with A = {1, m, 7,8}. b) Given a topological space (X, t) and Kς X. Prove that ext(K) = int(K^c) c) Let B = [0,1]. Show that int(B) = [0,1].