Answer:
A. decreases if banks increase their desired reserve ratio
Step-by-step explanation:
Since, the money multiplier is the amount of money produced by banks with each dollar of reserves,
In other words,
It estimates, how an initial deposit can lead to a bigger final increase in the total money supply.
For example :
If a commercial bank gains deposits of 1 crore and this leads to a final money supply of 10 crore, the money multiplier would be 10.
That is,
[tex]\text{Money multipliers}=\frac{1}{\text{Reserve ratio}}[/tex]
[tex]\implies \text{Money multipliers}\propto \frac{1}{\text{Reserve ratio}}[/tex]
Therefore, the money multiplier decreases if banks increase their desired reserve ratio