The correct answer is option 1: Political statecraft. Kautilya`s "Arthashastra" is an ancient Indian treatise on political science and governance. It primarily focuses on the principles and strategies of political statecraft. It provides guidance on various aspects of governance, including the establishment and maintenance of a strong and efficient political system, diplomatic relations with other states, strategies for war and military campaigns, methods for managing the economy, and policies for maintaining social order and stability. Although the other options mentioned, such as social aspects, economic doctrines, and military aspects, are also addressed to some extent in the "Arthashastra," the main emphasis of the text is on political statecraft and the art of ruling a kingdom effectively.