It's called : C. bait and switch
Here's the example scenario
A salesman offered you and iphone 5 , and describing its features to you, but he doesn't have an actual stock of Iphone 5
You seems interested to buy the Iphone 5 and tell him that you want to buy it, and then they pretend to go to the back of the store to get it
but when he coome back to you, he say something like " Sorry sir, it seems that we're out of stock of Iphone 5, but we have more stocks of Iphone 6 which have a better feature than Iphone 5 but with slightly higher price, would you be interested? "
