39. In 2019, Alex earned $12,000 in net investment income and incurred $16,000 of investment interest expense. Alex paid off the loan in early 2020, so he only paid $4,000 of investment interest expense in 2020. He earned $10,000 of net investment income in 2020. How much investment interest expense can Alex deduct in 2020? A) $0 B) $4,000 C) $8,000 D) $10,000