How does this to explain the variations in dissemination of chinese culture among the regions?

Http://wps.pearsoncustom.com/wps/media/objects/2426/2484749/chap_assets/studyguide/ste_sg_ch18.pdf

On page 8, the same question was given based on the link. It has another question connected to this question. It pertains to a picture asking the relationship of insular and peninsular regions such as Japan, Korea, and Vietnam's geophysical and spatial relations can be associated with the variations and dissemination of Chinese Culture.  Since these countries are near China, Chinese culture can then bring its influences of culture through trade. It is a common activity shared among these countries. Commerce can bring ties, cultural understanding, and relationship.