If an investor expects interest rates to go up, the investor buying a CMO security will most likely purchase:

the last tranche in a sequentialpay CMO.

a floatingrate tranche in a CMO.

a PAC tranche in a CMO.

In a CMO with a PAC tranche and a support tranche, the tranche that most likely has higher prepayment risk is:

the PAC tranche.

the support tranche.

neither, as both have roughly the same amount of prepayment risk.