Analyze the relationship between 'Syriza' and 'Alexis Tsipras' within the context of the input sentence.
Options: product/material produced, distribution format, platform, chairperson

While the new law will come as a relief to Prime Minister Alexis Tsipras -- who is negotiating a new bailout worth up to 86 billion euros ($93 billion) over three years -- it saw him suffer a major rebellion amongst MPs in his leftist Syriza party for the second time in a week.
chairperson