Question

A red sleeveless dress has been a fast seller at a clothing store. Which of these might raise the price of the dress?

1. A change in fashion season, requiring the store to put the dress out of stock
2. A competitor's product going on sale midway through the season
3. A decrease in sales of the dress during the second half of the season
4. A reduction in the number of dresses available from the manufacturer

I think is 1 or 4.... I'm having a hard time figuring this one out, and all I need is just a little guidance!!