Use the given decision tree to answer the questions that follow. Payoffs are costs. P(s2) = 0.2 $5,200 0.65 A $3,000 $3,900 B $3,700 a a) The expected value at node A, EV ( A) = $ b) The expected value at node B, EV (B) = $ c) The expected value at node c, EV(C) = $