the number inside the parenthesis includes the interest rate ( annual percentage
looking at the possible functions, if you raise the interest rate to the power of 12, you would need to divide the number of years (t) by 12 as well
so the function could be rewritten as A=1000(1.023^12)^t/12
since the annual percentage rate is 2.3% ( 0.023)
divide 0.023/12*100 = 0.19% per month interest
