Answer: expected maturities.

**Explanation:** - **Option A (Incorrect):** This refers to credit tranching, not time tranching. In credit tranching, multiple bond classes or tranches exist, and they differ in how losses from borrower defaults are shared. - **Option B (Correct):** Time tranching involves creating bond classes with different expected maturities. This structure allows investors to choose tranches based on their preferred investment horizons. - **Option C (Incorrect):** Tranching does not alter the underlying collateral. Instead, it determines how losses or prepayments are distributed among the bond classes. The collateral remains unchanged, but the tranches differ in their exposure to risks like defaults or prepayments. **Reference:** Fixed Income - Define prepayment risk and describe time tranching structures in securitizations and their purpose.

Author: LeetQuiz Editorial Team