On 31 March 2013, Gerald borrowed money from his parents. He promised that he would repay the money with interests at 7% p.a. on 31 March 2018. The total amount that he was due to pay his parents at that time was exactly $8,000 but he started his studies at university so he couldnt afford to repay the loan. If interest continues to accrue, what amount must Gerald pay on 31 March 2021 to fully pay off the loan? Select one:

a. $13,125.69 b. $9,712.56 c. $13,745.49 d. $9,800.34