Answer:
The question is incomplete since the requirements are missing, but I guess that it deals with the bank's ability to create money.
When you deposit money into a bank account, the bank will then lend most of that money to other clients. This is possible due to the money multiplier = 1 / required reserve rate = 1 / 4% = 25
the total increase in money supply = $12,000 x 25 = $300,000
