For each of the following situations, indicate the amount of the penalty that could be imposed on the tax return preparer: a. A tax return preparer understates the taxpayer's tax liability with a frivolous position and does not disclose the position. The greater of $ or percent of the income derived by the tax preparer for an undisclosed unrealistic position. b. A tax return preparer fails to furnish his identifying number. $ c. A tax return preparer aids a taxpayer (an individual) in understating a tax liability. $ d. A tax return preparer endorses and cashes a client's tax refund check.