Which of the following statements regarding scenario analysis and decision trees is not correct?

a$.$ Each possible outcome is shown as a branch on the tree.

b$.$ The probabilities can vary on the branch lines as long as they total $100\%.$

c$.$ The probabilities on the various branch lines must equal $100\%$ divided into equal amounts.

d$.$ Each branch shows the cash flows and probability of a scenario laid out as a timeline.