Virginia is a cash-basis, calendar-year taxpayer. Her salary is $20,000, and she is single. She plans to purchase a residence in 2017. She anticipates her property taxes and interest will total $7,200. Each year, Virginia contributes approximately $1,000 to charity. Her other itemized deductions total approximately $800. For purposes of this problem, assume that 2017 tax rates, exemptions, and standard deductions are the same as for 2016.

a. What will her gross tax be in 2016 and 2017 if she contributes $1,000 to charity in each year?

b. What will her gross tax be in 2016 and 2017 if she contributes $2,000 to charity in 2016 but makes no contribution in 2017?

c. What will her gross tax be in 2016 and 2017 if she makes no contribution in 2016 but contributes $2,000 in 2017?

d. Alternative c results in a lower tax than either a or b. Why?