4. Exactly six years ago, Xen borrowed $325,000 to buy a house. The fixed annual interest rate on the 30year loan is 4.90% p.a. The loan requires monthly payments, the first payment was made exactly one month after Xen bought the house, and Xen has made every payment for the past six years on time. Because interest rates have recently decreased, Xen is considering refinancing the loan. Assuming that Xen just made the 72nd payment on the loan, what is the remaining balance on the loan (i.e., the amount that Xen would need to refinance to completely pay off the current loan)? a. $285,236.60 b. $278,361.82 c. $271,367.55 d. $266,147.84 e. $291,783.29