In the world of securitization of mortgages, a CMO is a structured MBS where investor tranches have different rights to different sets of cash flows $($think champagne fountain$).$This was created to protect the investor from:

A$.$ No$-$Doc risk $($Instructor note: No doc mortgage is a type of mortgage that does not require verification on the borrower's income, employment or assets.$)$

B$.$ Re$-$sale risk

C$.$ Default risk

D$.$ Prepayment risk