10. In the decision tree structure a. The square denotes a decision point and a circle denotes a state of nature b. The square denotes a probability and a circle denotes a state of nature C. The square denotes a state of nature and a circle denotes a decision point d. The square denotes a decision point and a circle denotes a payoff 11. The basic decision environment categories are A) certainty and risk B) risk and uncertainty C) certainty and uncertainty D) certainty, uncertainty and risk