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 $fill in the blank 4050a6fedff0012_1 or fill in the blank 4050a6fedff0012_2 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. $fill in the blank 4bc295062032fac_1

c. A tax return preparer aids a taxpayer (an individual) in understating a tax liability. $fill in the blank e65638040f8cfe5_1

d. A tax return preparer endorses and cashes a client's tax refund check. $fill in the blank 07521d069016f81_1