Loans Are Typically the Highest-Return Assets on a Bank's Balance

Loans are typically the highest-return assets on a bank's balance sheet. If this is so, then why do banks sell these loans in a process called securitization?

A) Banks only sell the loans they think are uncollectible
B) Investors are willing to pay more for the loans than the bank can earn
C) The Federal Reserve requires banks to raise equity in this manner
D) Banks raise reinvestible funds and generate fee income from origination and servicing of these loans
E) None of the above