What is shown in the image?

The correct answer is C. "Route to airport." In the image, the sign indicates the direction or route to the airport, which is important information for drivers who need to head to the airport for a flight or other reasons. This sign is specifically pointing towards the airport, helping drivers navigate and find their way to the airport easily.

Option A, "Air show ahead" is incorrect because the sign is not indicating an air show but directing towards the airport. Option B, "Airplane landing" is also incorrect as the sign is not related to an airplane landing but to the route to the airport. Option D, "Watch out for planes" is not the correct answer as the sign is not warning drivers to watch out for planes but guiding them towards the airport.