Final answer:
Bank A has excess reserves of $9.3 million. Therefore, the correct option is A.
Step-by-step explanation:
To determine the excess reserves of Bank A, we need to subtract the required reserves from the total reserves. The required reserve ratio is given as 9 percent. We can calculate the required reserves by multiplying the checkable deposits by the required reserve ratio. In this case, the required reserves are $510 million x 9% = $45.9 million. The excess reserves are then $55.2 million - $45.9 million = $9.3 million.