Which factor that affects demand is MOST likely occurring when retail stores place clothing on sale?

Answer: Change in price.

Demand refers to the amount of some product that a consumer is willing and able to purchase. Willingness can be affected by modifying either the product or the consumer's tastes and preferences. On the other hand, ability can be affected by changing the population's income, or the product price. If products become cheaper, people will be willing to buy more (increase in demand). This is the mechanism at work when stores place clothing on sale.

Change in consumer taste.