Consider the IntvlPart greedy algorithm and the following three greedy strategies we discussed in class: (a) earliest finish time first, (b) shortest interval first, and (c) fewest conflicts first. For each of these three greedy strategy, either prove or disprove if it is an optimal greedy strategy. If you want to disprove it, provide a counter example. For simplicity, your counter example must contain no more than five lectures.