What is the immediate effect of her deposit on the money supply?

The immediate effect of her deposit on the money supply is that it increases the reserves of the bank, allowing the bank to lend more money. When she deposits funds, the bank is required to hold a fraction as reserves but can lend out the excess, effectively creating new money through the lending process. This process can lead to a multiplier effect, where the initial deposit results in a greater overall increase in the money supply as loans are made and re-deposited.