Final answer:
Cyber-espionage is a primary factor that has increased tensions between the United States and China in the twenty-first century, along with economic trade challenges, the status of Taiwan, and human rights issues.
Step-by-step explanation:
Tensions Between the United States and China
Among the factors that have increased tensions between the United States and China in the twenty-first century, cyber-espionage is a significant one. Economic trade challenges, the contested status of Taiwan, and human rights are other major issues affecting the relationship between these two countries. Cyber-espionage involves cyber attacks and theft of sensitive information, which has been a source of strain as the US has accused China of engaging in such activities.
While the other options such as disputes over common borders, Chinese interference in Japan, and rights in the Gulf of Mexico do not accurately reflect the tension points between the US and China, the issues around economic conflict and military tensions remain pivotal. The political and military rise of China, and its role in international economics, like lending money to the United States government, are critical elements in this complex relationship.
The complex interdependence between the US and China, despite the economic linkages, has not prevented the occurrence of strategic rivalry and conflict in areas such as technology and influence in the South China Sea, highlighting the multi-faceted nature of their international relations.