If banks decide to hold some of their excess reserves instead of lending them all out, then:
A.
. the money multiplier will be less than 1 divided by the required reserve ratio.
B.
. a loan of $1 will lead to a change in the money supply by a multiple amount equal to 1 divided by the required reserve ratio.
C.
. the money multiplier becomes 1 divided by the excess reserves.
D.
. depositors will have to borrow more in order to increase the money supply.