For the current tax year, David, a married taxpayer filing a joint return, reported the following: Investment income from interest $24,000 Investment expenses other than interest $3,000 Interest expense on funds borrowed 10 years ago to purchase investment property $70,000 What is the maximum amount that David can deduct in the current year as investment interest expense?

a. $24,000

b. $20,000

c. None of these

d. $21,000

e. $7,000