Definition: 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: UK #39;s BT changes mobile partner, plots comeback Britain #39;s BT Group Plc re-entered the mobile phone market yesterday, launching its own branded cellphone service on Vodafone #39;s network as it looks to boost revenues with its fixed-line business in decline.

Sci/Tech