Which of the following is not an interest rate swap?

a. A fixed for floating swap involving exchange of fixed interest rate payments in one currency for floating payments in the same currency but in which the swap NPV at inception is non zero.

b. A floating for floating swap in which one floating rate in a currency is exchanged for another floating rate in the same currency.

c. A fixed for floating swap in which a fixed interest rate payment in one currency is exchanged for floating interest rate payments in another currency.

d. A fixed for floating swap involving exchange of fixed interest rate payments in one currency for floating payments in the same currency but in which the payments are computed on principal that is reduced in a pre-specified manner during the life of the swap.

e. None of the above.