Answer:
It is the Bait and switch strategy.
Step-by-step explanation:
Let re-visit the concept of Bait and switch strategy first before we apply it to explain the strategy applied by the Auto dealer.
The Bait and Switch strategy is the strategy when a company try to attractive customer by a lower-price product, yet unavailable ( low price is used as a "bait"). Once the customer get to them, they will try to sell the similar, yet, higher-price product ( that is, they do the switch from low-price to higher-price product).
In the described situation, the Auto dealer tries to lure Shawn in with the lower price of the old sedan model which is already sold out. Once he turns out, the Auto dealer tries to sell him the more modern model with higher price.