Liberal theory (idealism) was also formulated in the 16th century and forward. Thus, realism was not the sole theory International Relations scholars took up. Classical liberalism is a political philosophy and an ideology in which primary emphasis is placed on securing the freedoms of the individual by limiting the power of the government. Classical liberalism is built on ideas that had already arisen by the end of the 18th century, such as selected concepts of Adam Smith, John Locke, Jean-Baptiste Say, Thomas Malthus, and David Ricardo. Idealism promotes toleration, reason and progress, equality before the law, and an open economy. It suggests that states will search for long-term mutual gains instead of short-term individual gains—if their security and sovereignty are not significantly diminished or threatened. Idealism’s terms underlie liberal political thought.

As also understood from the information given, the correct answer is D. The statements in the options I, II, IV, V and VI are correct. The statement in the option III is not correct. Classical liberalism is built on ideas that had already arisen by the end of the 18th century, such as selected concepts of Adam Smith, John Locke, Jean-Baptiste Say, Thomas Malthus, and David Ricardo.