Which of the following statements best describes the Khmer Empire? A. It was a nomadic empire that inhabited Mesopotamia about 3,000 years ago. B. It was an advanced civilization that developed in South America around 100 CE. C. It developed the world’s largest pre-industrial city between 800 and 1431 CE . D. It was an empire of nomads who roamed the grasslands of northern Asia. Please select the best answer from the choices provided.