Which of the following is not a rule of natural justice?

A) A person affected by a decision must be notified that the decision is to be made.
B) A person must be given an opportunity to put his side forward.
C) A person must be given the opportunity to cross-examine a witness or complainant if that is the only way to defend himself.
D) A person must be allowed to retain a lawyer.
E) The decision maker must be impartial.

The rules of natural justice primarily focus on fair hearing and impartiality, including the right to be notified of decisions, the opportunity to present one's case, and the requirement for the decision-maker to be impartial. The specific right to retain a lawyer, while often part of fair legal processes, is not considered a fundamental rule of natural justice itself, as these principles can apply in situations where legal representation is not relevant or required.