Choice "B" is correct. For each tax return prepared, a tax preparer must retain either the taxpayer's name and identification number, or a copy of the return.Choice "a" is incorrect. This is not an item that a tax preparer is required to retain.Choice "d" is incorrect. A tax preparer is not required to retain workpapers used in preparing a tax return, although doing so is often a sound business practice. Among other reasons, the workpapers could be beneficial in the event of an audit, or in the preparation of the following year's tax return for the client.Choice "c" is incorrect. This is not an item that a tax preparer is required to retain.