Alicia borrowed $8,500 at 6% ordinary interest for 180 days. After 40 days, she made a partial payment of $2,000. After another 70 days, Alicia made a second partial payment of $2,000. What is the final amount due on the loan?
a. $4,687.21
b. $4,684.62
c. $4,500.50
d. $4,755.00