If an agency prepares an appendix to an environmental impact statement the appendix shall:
(a) Consist of material prepared in connection with an environmental impact statement (as distinct from material which is not so prepared and which is incorporated by reference (Sec. 1502.21)).
(b) Normally consist of material which substantiates any analysis fundamental to the impact statement.
(c) Normally be analytic and relevant to the decision to be made.
(d) Be circulated with the environmental impact statement or be readily available on request.