[Solved] According to the authors, if anything in human life should be voluntary and spontaneous, it is: A) sexual regulation. B) animalistic instinct. C) erotic behavior. D) psychological understanding. Thirty Year Mortgage: A long-term home loan typically repaid over 30 years through fixed monthly payments, often with a fixed interest rate. Monthly Payment: The amount paid each month on a loan, mortgage, or other debt obligation. APR: Annual Percentage Rate; the annual rate charged for borrowing or earned through an investment, accounting for fees and compound interest. APR Discount Rate: The annual percentage rate that represents the actual yearly cost of funds over the term of a loan, including any fees or additional costs associated with the transaction.