The most common type of mortgage-backed security is:

A) The mortgage pass-through, a security that has the borrower's mortgage payments pass through the trustee before being disbursed to the investors.

b) Collaterized mortgage obligations, a security which reduces prepayment risk.

c) The participation certificate, a security which passes the borrower's mortgage payment equally among all the owners of the certificate.

d) the securitized mortgage, a security which increases the liquidity of otherwise illiquid mortgaes,