Answer:
A deontological ethical system emphasizes a duty directed toward what ought to be right.
Explanation:
Deontological ethics believes that principle is primary, while consequence is secondary or even irrelevant. In other words, the acts in themselves are inherently good or evil, regardless of the consequences. Deontology is concerned with duties and rights and is, for that reason, the best answer to complete the sentence.
We can eliminate the existential ethical system since it defends the idea that no actions are inherently right or wrong.
We can also eliminate the teleological ethical system, since it focuses on consequences (the ends) of an act.
Libertarian ethics is also not a good option. It believes people should be free to judge their own interests, making the choices they think are the best ones for themselves.