Take context from the input text and decide on the accurate relationship between 'Freddie Mac' and 'mortgage loan' from the options provided.
Options: parent organization, product/material produced, subsidiary, platform

Freddie Mac is guaranteeing four classes of senior securities issued by a third party trust, the FRESB 2015-SB2 Mortgage Trust, and is acting as mortgage loan seller and master servicer.
product/material produced