In which of the following cases is a worker counted as unemployed? Explain.

a. Rosa, an older worker who has been laid off and who gave up looking for work months ago

b. Anthony, a schoolteacher who is not working during his three-month summer break

c. Kanako, an investment banker who has been laid off and is currently searching for another position

d. Sergio, a classically trained musician who can only find work playing for local parties

e. Natasha, a graduate student who went back to school because jobs were scarce