Explain whether each of the following would be expensed on the income statement in2007 or in some later year, and why.

a. Inventory purchased in 2007 but sold in2008.

b. Estimated warranty costs for goods sold in 2007; the warranty servicing will take place in 2008 and 2009.

c. Bad debts caused by 2007 sales; the actual bad receivables will not be identified until a later year.

d. Research and development costs incurred in 2007 but aimed at producing a better product in later years.