Which of the Following Was an Indication of Cultural Contact

Which of the following was an indication of cultural contact with the Longshan culture?

A) In different regions, the dead were left exposed to the elements, leaving few burial sites for archaeologists to investigate.
B) In different regions, city-states began to arise.
C) In different regions, people began to produce similar pottery and tools.
D) In different regions, large-scale dynastic systems emerged that structured the political life of the society.