25. For the year ended December 31, 2018, David, a married taxpayer filing a joint return, reported the following: Investment income from taxable interest $40,000 Investment expenses $5,000 Interest expense on funds borrowed in 2018 to purchase investment property $50,000 What is the maximum amount that David can deduct in 2018 as investment interest expense? a. $50,000 b. $40,000 c. $45,000 d. $35,000 e. None of the above