(3) capitalism -- Wealth of Nations is the correct answer.
(1) is incorrect because The Prince involved absolute power, not colonialism.
(2) is incorrect because the Sadler Report involved labor laws, not militarism.
(4) is incorrect because The Communist Manifesto involved Communism, not monotheism.
(3) is correct because Adam Smith's "The Wealth of Nations" practically served as the Bible of capitalism in the 18th and 19th centuries.
