Fifteen years ago ABC Inc. took out a $$100$ million loan with an interest rate of $6$ percent compounded quarterly over its forty$-$year life. With interest rates having risen recently, ABC is now looking to potentially refinance the loan.

A$)$ The accounting department would like to know how much interest was paid on this loan last year

B$)$ If new debt with an interest rate of $4\mathrm{.}75$ percent compounded quarterly can be raised with a $2$ percent flotation cost, should they refinance this loan?

C$)$ At what interest rate would ABC begin to reconsider their decision