Every day on his way to work, frederic stops by a large chain hotel at which he is not staying, walks into the lobby, and himself to the continental breakfast. he believes this is the right thing to do because it saves him a lot of money and is very convenient. what ethical theory is he using to justify his actions?

I believe the answer is: Ethical Egoism

Ethical egoism refers to the view that encourage people to pursue their own self-interest above all else.
This view believe that by following our true interest, the society in general would truly find what thing is the most desired by the majority of people, which would help us in making decisions based on concencus