A. Incorrect because mortgage pass-through security cash flows are uncertain because they depend on actual prepayments. This risk is called prepayment risk. B. Incorrect because the creation of a [collateralized mortgage obligation] cannot eliminate or change prepayment risk; it can only distribute the various forms of this risk among different bond classes. C. Correct because a critical investment feature that distinguishes CMBS from RMBS is the protection against early prepayments available to investors known as call protection. An investor in an RMBS is exposed to considerable prepayment risk because the borrower has the right to prepay a loan, in whole or in part, before the scheduled principal repayment date. The discussion of CMOs highlighted how investors can purchase certain types of tranches to modify or reduce prepayment risk. CMBS investors have considerable call protection, which results in CMBS trading more like corporate bonds than RMBS.