Mark the incorrect answer. Estimated income tax payments:

	a.	Need not be filed if the estimated tax, after subtracting withholding, can reasonably be expected to be more than $1,000.
	b.	May be based on the amount of the tax liability for the prior year.
	c.	If inadequate, may result in nondeductible penalties.
	d.	Are made in four installments on April 15, June 15, and September 15 of the tax year and on January 15 of the following year.