Historically, different conceptions of ethics are observed. One of them advocates that good conduct is useful conduct, that contributes to the well...

Historically, different conceptions of ethics are observed. One of them advocates that good conduct is useful conduct, that contributes to the well-being (happiness) of the greatest number of people. This approach is called:
a) existentialism.
b) relativism.
c) naturalism.
d) utilitarianism.
e) contractualism.