Answer:
C) Structural unemployment
Step-by-step explanation:
Structural unemployment: This is a type of unemployment caused by a change in the economy. The change could lead to workers not having the required skills and knowledge to fit into an organization any longer. The change in the economy could be caused by factors such as technology advancement, government policy or competition among firms.
In structural unemployment, jobs are usually available but workers don't have the required skills to fit into the available jobs.
From the question, the structural unemployment arises as a result of advancement in technology where people no longer need to read on books but read on electronic devices. The bookstores will be out of job until they could upgrade their services to electronic bookstores and this might take some time.