Please help me answer the following questions. Please provide an explanation for each if you can. Thank you so much!

29. Cathy buys a house in 2020 (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 for 2020 is $75,000, how much is her itemized deduction for interest expenses for 2020?

1. $75,000
2. $50,000
3. $37,500
4. $0
5. None of these

30. Which of the following prepaid interest is deductible immediately?

1. Points paid to obtain a loan for the purchase of a principle residence
2. Prepaid personal credit card interest
3. Business interest prepaid by a cash basis taxpayer
4. Business interest prepaid by an accrual basis taxpayer

31. If an individual taxpayer contributes capital gain property to a qualified public charity and wants to deduct fair market value, the deduction would be subject to which of the following limits?

1. 20 percent of the taxpayer's AGI.
2. 30 percent of the taxpayer's AGI.
3. 40 percent of the taxpayer's AGI.
4. 50 percent of the taxpayer's AGI.