Instructions: In this task, you are given a news article. Your task is to classify the article to one out of the four topics 'World', 'Sports', 'Business', 'Sci/Tech' if the article's main topic is relevant to the world, sports, business, and science/technology, correspondingly. If you are not sure about the topic, choose the closest option. Note that URLs in the text have been replaced with [Link].
Input: Citigroup Hits Back at Parmalat  MILAN (Reuters) - Citigroup on Friday launched a legal  challenge against Parmalat's restructuring plan, hitting back  after the bankrupt food group took the world's biggest bank to  court and rejected its claims for credit repayment.
Output:
Business