In 2017 (old law), Cathy bought a house (her principal residence) for $2,000,000, paying $500,000 down and borrowing the other $1,500,000 at 5% interest. If her interest expense in 2018 (new law) is $75,000, how much will her maximum deduction for interest expenses be? Question 18 options: 1) $75,000 (old law rules "grandfathered" in) 2) $50,000 (old law rules "grandfathered" in) 3) $55,000 (old law rules "grandfathered" in) 4) $0 (old law rules not "grandfathered" in) 5) None of these