The correct answer is D. All of the above.
Utilitarianism is a theory of morality that advocates actions that foster happiness or pleasure and opposes actions that cause unhappiness or harm. Jeremy Bentham (1748-1836) is considered the founder of utilitarianism. He defined utility as “the greatest happiness of the greatest number.” James Mill (1773-1839) was a British philosopher, economist, and civil servant. He was a follower of Jeremy Bentham and helped to popularize utilitarianism. Henry Sidgwick (1838-1900) was a British philosopher who is considered one of the most important utilitarian thinkers. He argued that utilitarianism is the only ethical theory that is both rational and consistent.
Utilitarianism has been criticized for being too simplistic and for not taking into account the rights of individuals. However, it remains a popular theory of morality and has been influential in many areas of thought, including law, economics, and politics.