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: Books have been written about him, a film was devoted to following his every move on a football field and now the career of French icon Zinedine Zidane has been immortalized in bronze. From Cannes to Real Madrid -- his first and last clubs -- Zidane's career was characterized by moments of audacity and greatness. None more so than when he scored a brace which helped win the World Cup for France on home soil in 1998, or one of the greatest goals of all time in the 2002 European Champions League final in Real Madrid's 2-1 win over Bayer Leverkusen in Glasgow.A bronze statue of Zinedine Zidane head-butting Marco Materazzi unveiledThe piece outside Paris' Pompidou Museum is the work of Adel AbdessemedThe headbutt occurred in the 2006 World Cup final, which Italy won on penaltiesZidane is regarded as one of the finest footballers in history 
 Question:Exactly what Materazzi said to draw such a violent reaction from _ remains unknown.

Zinedine Zidane