Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: (CNN) An Australian senator with close ties to a prominent Chinese businessman and political donor has stepped down amid growing concerns about China's influence over Australian politics. Opposition Labor party Senator Sam Dastyari announced his resignation early Tuesday morning after weeks of pressure, saying he wanted to spare his party further distraction. "I have always honored my parliamentary oath, I've always acted with integrity and I remain a loyal patriotic Australian," Dastyari told reporters as he announced his resignation. The Dastyari controversy prompted the introduction of new security laws last week, including a complete ban on foreigners donating to Australian political parties.The Chinese government reacted furiously to allegations of influence in AustraliaDastyari has previously been accused of working closely with Chinese donors 
 Question:"The Chinese integrity of its borders is a matter for _," he told the gathering.

Chinese