Answer:
lower your mortgage interest rate
Explanation:
The higher your credit score, the __lower your mortgage interest rate__.
Because the higher your credit score, the less risk you represent for a lender, so it will most likely grant you a lowest rate for your mortgage/loan.
The "lower your savings interest rate " is not the answer because savings interest rates are not related to the credit score...
"higher your car loan rate " and "higher risk you are to a creditor " are consequences of a low credit score.