Question 1 (Unit B1) - 23 marks For each of the following sets, with the binary operation given, determine by checking the group axioms whether or not it is a group. (a) ({5, 10, 20, 25, 35, 40}, X45) [7] (b) (C, o), where zow = z + w - 3i [12 (c) (N, *), where a * b = a' [4]