Which One of These Statements Best Describes How Policy Checkpoints

Which one of these statements best describes how policy checkpoints evaluate the installed policy on a ProxySG?

A) The Client In checkpoint decides which rules will be evaluated by the other checkpoints.
B) At each checkpoint, a decision is made whether to allow or deny the transaction.
C) The Server In checkpoint decides which rules will be evaluated by the other checkpoints.
D) Relevant rules are evaluated at each checkpoint based on the information about the transaction that is available at that point.