In a fractional-reserve banking system, an increase in reserve

a. increases both the money multiplier and the money supply.
b. decreases both the money multiplier and the money supply.
c. increases the money multiplier, but decreases the money supply.
d. decreases the money multiplier, but increases the money supply.

b. decreases both the money multiplier and the money supply.

Explanation:

An increase in reserve requirements will decrease the money supply in the economy. This is because, banks and other financial institutions will have lower excess reserves to lend out to the public hence decreasing the overall amount of borrowing . Based on money multiplier, the explanation is based on the following equation;

Money multiplier = 1/ required reserve , if the required reserve increases then the fraction will be smaller. Therefore, the money multiplier will decrease too.

answer; post closing trial balance;