Which of the following best describes how a sell stop at 39 order would be filled?

A sell stop order is designed to trigger a market sell order once the price falls to a specified level, in this case, 39. When the market price reaches 39, the sell stop order becomes active and is executed at the next available price. This means that if the market trades down to 39, the order will be filled at the next price point that buyers are willing to purchase the stock.

In the context of market conditions, if there are no buyers at exactly 39, the order will fill at the next lower price, which is why the answer correctly identifies this scenario. This mechanism is used typically to limit losses or protect gains in a declining market. Understanding how sell stop orders operate is essential for effective trading strategies, particularly in volatile markets where prices may skip levels due to high volume.