Brian and Sharon want to keep $500000 of their savings FDIC insured. They could accomplish this by

Dividing it equally and depositing it at two different banks.

dividing it equally into stocks and mutual funds at the brokerage firm.

Dividing it equally into a mutual fund and a checking account at a bank.

Investing $250000 in a money market mutual fund and $250000 in a savings account at the bank.