Final answer:
b) Mortgage bankers
Mortgage bankers are the ones who service mortgage loans, including those they have sold to investors, as they manage the loan's administration and collect payments throughout the loan's life.
Step-by-step explanation:
Among the entities listed, mortgage bankers service mortgage loans, including those they have sold to investors. Mortgage bankers originate loans and then can service them throughout the life of the loan, collecting payments and managing the loan's administration, even after the loans are sold on the secondary market. The primary role of mortgage brokers is to connect borrowers with lenders, while loan originators are typically the ones within banks or lending institutions who initially generate the loan. Loan processors handle the paperwork and application process but do not service the loan post-origination.