The correct answer is (a) Oppenheim.
Oppenheim is a German-British jurist who is considered to be one of the founders of modern international law. He is best known for his treatise International Law, which was first published in 1905 and is still considered to be one of the most authoritative works on the subject.
Brierly is a British jurist who is also considered to be one of the founders of modern international law. He is best known for his book The Law of Nations, which was first published in 1928 and is still considered to be one of the most authoritative works on the subject.
Bentham is an English philosopher who is considered to be one of the founders of utilitarianism. He is best known for his book An Introduction to the Principles of Morals and Legislation, which was first published in 1789.
Kapoor is an Indian jurist who is considered to be one of the leading experts on international law in India. He is best known for his book International Law: A Textbook, which was first published in 1997.
Oppenheim is the most likely candidate to have coined the term “international law” because he was one of the first jurists to write extensively on the subject. He is also the author of one of the most authoritative works on the subject.