Answer:
(a) Yes. It is an opportunity cost of new job because the additional time he spent commuting is a cost, as he can utilize that time in doing something else.
(b) Yes. It is also an opportunity cost because if a person wants to join a new job then he have to give up his current job. So, the earning of $45,000 from his current job is the opportunity cost of accepting the new job.
(c) No. It is not an opportunity cost but it is an additional benefit from the new job because he is not sacrificing anything to obtain this benefit.