The correct answer is: B. highest airport.
Lhasa Gonggar Airport is the highest airport in the world, with a runway elevation of 4,334 meters (14,219 feet). It is located in Lhasa, the capital of Tibet Autonomous Region, China. The airport was opened in 1965 and has one runway. It is served by several airlines, including Air China, China Eastern Airlines, and China Southern Airlines.
The other options are incorrect. The largest airport in the world is King Fahd International Airport in Dammam, Saudi Arabia. The lowest airport in the world is Qamishli Airport in Syria. The busiest airport in the world is Hartsfield-Jackson Atlanta International Airport in Atlanta, Georgia.