Indicate and explain whether each of the following independent situations should be treated as a temporary difference or a permanent difference.

(a) For accounting purposes, a company reports revenue from installment sales on the accrual basis. For income tax purposes, it reports the revenues by the installment method, deferring recognition of gross profit until cash is collected.

(b) Pretax accounting income and taxable income differ because 80% of dividends received from U.S. corporations was deducted from taxable income, while 100% of the dividends received was reported for financial statement purposes.

(c) Estimated warranty costs (covering a three-year warranty) are expensed for accounting purposes at the time of sale but deducted for income tax purposes when paid.