Explanation: Event nodes represents the possible uncertain outcomes of a risky decision, with at least two nodes to illustrate the positive and negative range of events. Probabilities are always attached to the branches of event nodes.
Incorrect Answers:
A: Root node is the starting node in the decision tree, and it has no branches.
C: End node represents the outcomes of risk and decisions and probability is not attached to it.
D: It represents the choice available to the decision maker, usually between a risky choice and its non-risky counterpart. As it represents only the choices available to the decision makers, hence probability is not attached to it.