Please show all calculations.

9. In 2019. Perla earned $10,000 in net investment income and incurred $15,000 of investment interest expense. Perla paid off the loan in early 2020. so he only paid $3,000 of investment interest expense in 2020. She earned $12,000 of net investment income in 2020. How much investment interest expense can Perla deduct in 2020? A) SO B) $3,000 C) $7,000 D) $8,000