Using the graph below, a) When probability of high settlement is 12% and the probability of medium settlement is 40%, what is the optimal strategy? b)When probability of medium settlement is 20%, what is the highest probability of high settlement so that the Accept strategy to be optimal?

Strategy Region for Node 'Settle ?' 100% 90% * Refuse 80% A Accept 70% 60% Probability of Medium ($5) Settlement 50% 40% 30% 20% 10% 0% 4% 8% 0% 20% 40% 36% 28% 32% 16% 24% 12% Probability of High ($10.3) Settlement