Ryan Cozzens withdraws $400 from his checking account at the local bank and keeps it in his wallet.

a. How will the withdrawal change the T-account of the local bank and the money supply?

b. If the bank maintains a reserve ratio of 10%, how will it respond to the withdrawal? Assume
that the bank responds to insufficient reserves by reducing the amount of deposits it holds until its level of reserves satisfies its required reserve ratio. The bank reduces its deposits by calling in some of its loans, forcing borrowers to pay back these loans by taking cash from their checking deposits (at the same bank) to make repayment.

c. If every time the bank decreases its loans, checkable bank deposits fall by the amount of the loan, by how much will the money supply in the economy contract in response to Ryan's withdrawal of $400?

d. If every time the bank decreases its loans, checkable bank deposits fall by the amount of the loan and the bank maintains a reserve ratio of 20%, by how much will the money supply contract in response to a withdrawal of $400?