From the perspective of the present world, of course, it is ancient Greece, and the ancient Indian civilization has basically died out. Of course, from the cultural point of view, the ancient China civilization basically retains not much except Chinese characters.
After all, the origin of modern civilization and democracy is ancient Greek civilization. The influence of ancient China civilization rarely crossed East Asia, but at most it had some influence on Central Asia, but with the rise of Islam, even Central Asia could not be influenced. And the influence of ancient India is basically limited to the South Asian subcontinent. Only the ancient Greek civilization, with the Renaissance and the strong rise of the West, expanded to the whole world.
It's a simple comparison. To understand the world now, we must understand modern western civilization, which is rooted in ancient Greek civilization. Without understanding ancient Indian civilization and ancient China civilization, its influence on understanding the world is basically negligible ~