A fixed-rate payer position in a swap is the correct choice because it allows the transformation of a floating rate liability into a fixed rate liability. In a swap contract, two parties agree to exchange one stream of cash flows against another stream. In this case, Ali would enter into a swap contract where he agrees to pay a fixed rate and receive a floating rate. The floating rate he receives from the swap contract would offset the floating rate he has to pay on the initial loan. Therefore, his net payment would be the fixed rate from the swap contract, effectively transforming the floating rate liability into a fixed rate liability. This strategy is often used by investors and companies to hedge against the risk of interest rate fluctuations.

Choice B is incorrect. Taking a short position in interest rate futures would not transform the floating rate liability into a fixed one. Instead, it would be used to hedge against falling interest rates, which is not Ali's concern here. He is worried about rising rates.

Choice C is incorrect. A long position in a forward rate agreement (FRA) allows the holder to lock in an interest rate for borrowing or lending money in the future. However, this does not convert a floating-rate liability into a fixed-rate one as it only hedges against future changes in interest rates and does not affect existing liabilities.

Choice D is incorrect. A short position on call options gives the holder the right to sell an asset at an agreed price before a certain date but does not provide any transformation from floating to fixed-rate liabilities.