The correct answer is a.
An example of structural unemployment is the technological revolution. Computers might have
eliminated jobs, but it also opened up new positions
for those who had the skills to operate the computers.
Frictional unemployment occurs when
workers and employers have inconsistent or incomplete
information. For example a person might be able to
get a job, but is holding out for a better paying
Cyclical unemployment results from
changes in the business
Natural unemployment is similar to
the long run average unemployment. It is important
to remember that 'full employment' is when the economy
is at its natural rate of unemployment.