Choice "D" is correct. Characteristic of a best practice in rendering tax advice is establishing in a tax memorandum relevant facts, evaluating the reasonableness of assumptions and representations, and arriving at a conclusion supported by the law and facts.Choice "a" is incorrect. Circular 230's "Best Practices" do not include the tax advisor's requesting written evidence from a client that the fee proposal for tax advice has been approved by the board of directors.Choice "c" is incorrect. Circular 230's "Best Practices" do not include the tax advisor's recommending to the client that the advisor's tax advice be made orally instead of in a written memorandum.Choice "b" is incorrect. Circular 230's "Best Practices" do not include the tax advisor's requiring the client to supply a written representation, signed under penalties of perjury, concerning the facts and statements provided to the CPA for preparing a tax memorandum.