Answer:
Jerry's case is not an example of underemployment.
Step-by-step explanation:
Because the meaning of underemployment is that when a person has a job that does not use all of his/hers skills, in this case, Jerry did not took a different job in which his skills were not exploited, he quit his job because he wanted to help his wife.
In John's case, he went from salesman to janitor.
In Marcus's case, he went from college student to bartender.
In Ellen's case, she went from PR assistant to cosmetic sales associate.
And all of them took those jobs because they were their last option.