From the chart given, it is clear that the answer to the given question is (D) Monica works for a utilities company, Travis is self-employed, and Maggie works for a power company.
Monica probably works for a utilities company since she is responsible for checking gas meters on houses, while Travis is more likely to be self-employed since he installs solar panels on houses – though he can be employed by a company which sells solar company installation services, but the option is available. Since Maggie works on power lines, she is most definitely employed by a power company.