Which of the following is the best example of structural unemployment?

A、Tim is looking for a job with flexible hours but has not been offered one yet.;
B、Vickie lost her job as a graphic artist at a movie studio because she did not have training in computer-generated animation.;
C、Kirby is seeking a job as an airline pilot, but the high union wages in the industry have limited the number of jobs available.;
D、Fatima lost her job at a packing plant but has not looked very intensively for a new job because she still has 2 months of unemployment insurance benefits left.