Berty needs to borrow $10,000. She wants to have the loan paid back by the end of three years. Calculate the interest she would pay for each of the four following options.

a) She makes one payment at the end of three years with simple interest at 4.2%.

b) She makes one payment at the end of three years with 4.2% interest, compounded quarterly.

c) She makes one payment at the end of three years with 4.2% interest, compounded daily.

d) She makes monthly payments over the three years. Interest is 4.2%, compounded daily.