问题如下：
In a securitization, thecollateral is initially sold by the:
选项：
A. issuer.
B. depositor.
C. underwriter.
解释：
B is correct. In a securitization, the loans or receivables are initially sold by the depositor to the special purpose entity (SPE) that uses them ascollateral to issuethe ABS.
A is incorrect because the SPE, often referred to as the issuer, is the purchaserof the collateral rather than the seller of the collateral.
C is incorrect because the underwriter neither sells nor purchases the collateral in a securitization. The underwriter performs the same functions in asecuritization as it does in a standard bond offering.
请解释depositor和underwritter? 包括哪些人？ seller是bank，bank是depositor?
