please explain

11. In 2019, Derrick earned $7,500 in net investment income and incurred $12,500 of investment interest expense. Derrick paid off the loan in early 2020, so he only paid $1,500 of investment interest expense in 2020. He earned $6,000 of net investment income in 2020. How much investment interest expense can Derrick deduct in 2020? A) $0 B) $1,500 C) $6,000 D) $12,500