Zac takes out a 15-year fully amortising personal loan with an interest rate of 6% p.a. compounded quarterly. The loan is repaid with quarterly payments made at the end of each quarter and the loan outstanding balance after the 20^th repayment is $125,646.55. After the 20^th repayment the bank increases the interest rate to 7.5% compounded quarterly.

A. Calculate the 20^th quarterly payment before the interest rate change. Express your answer to the nearest cent. 

B. Calculate the original loan amount that was borrowed from the bank. Express your answer to the nearest cent.

C. How long will it take Zac to repay the loan, if he wants to keep the same quarterly payment after the rate change, and the bank allows him to pay the loan over a longer period? Round up your answer up to the full quarter.