Which education level has the highest return on investment (roi)?

Having a bachelor degree from a college gives the highest returns on investments. People who go to college usually secure high paying jobs compare to their counterparts who have less education.
The type of college one attends also matter, for instance in USA, the college in the first position, which gives the highest return on investment is Massachusetts Institute of Technology  [MIT].

He would most likely be employed by a gov. agency or homeowner because he has the required skills that have to be known to apply and get hired into those jobs.

The answer is c.  the soft ware is unable to you because it is open for the public to use.