What happens first when the demand for a fad peaks and falls?

The quantity supplied and the price both go up.

The quantity supplied goes down, and the price goes up.

The surplus ends up for sale on the black market.

The price goes down, and the quantity supplied goes up.

If the demand for a fad peaks falls, the quantity will likely go down as the demand of the product got less making the quantity to be also less, though because of it, the price are likely to go up as their products are only few in quantity. The correct answer is the second choice above.