Answer: long a payer swaption.

## Explanation Let's analyze each position: **Payer Swaption**: Gives the holder the right to pay fixed and receive floating - **Long payer swaption**: Benefits when interest rates rise because the holder can exercise to pay a lower fixed rate than current market rates - **Short payer swaption**: Loses when interest rates rise because they must receive the lower fixed rate **Receiver Swaption**: Gives the holder the right to receive fixed and pay floating - **Long receiver swaption**: Benefits when interest rates fall because the holder can exercise to receive a higher fixed rate than current market rates When interest rates **increase**: - Long payer swaption becomes more valuable (correct answer A) - Short payer swaption loses value - Long receiver swaption loses value Therefore, an investor long a payer swaption benefits from rising interest rates.

Author: LeetQuiz Editorial Team