8.20 Given the following fault tree: Top event OR A B C AND AND OR E F H OR AND J K AND M N (a) Express the top event in terms of the basic events using Boolean logic. (b) Find the minimal cut sets. From this analysis, what are the top four basic events that should be the focus of the reliability design effort? (c) If the probability of each basic event is .02, approximate the probability of the top event.