Sometimes, if there is great demand, other producers will get in on it, and then the price may go down, the more similar products there are on the market. But popular vacation spots are usually more expensive than less popular ones, so B is the right answer.
If the demand for a product is high, typically the price of the product goes up. This is because when the demand is high, there are more people who want to buy the product than there are products available. As a result, sellers can increase the price and still find buyers. This is known as a seller's market. So, if you answered "goes up", that would be the correct choice.