(10) The greedy algorithm for the activity selection problem we discussed (Rosen pp. 417-421) can be stated as "Always select the activity having the earliest finish time, discard the activities incompatible with the selection just made, and work on the resulting subproblem." Show that the following greedy strategies (that replaces the underlined part) do not always yield an optimal solution for the activity selection problem, by giving a counterexample for each. (a) Always select the activity having the least duration. (b) Always select the activity that overlaps the fewest other activities. (c) Always select the activity having the earliest start time