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: Japan on alert as suspected Chinese sub detected in territorial waters (AFP) AFP - Japan was on alert after a suspected Chinese nuclear submarine entered its territorial waters, setting off a chase on the high sea amid mounting disputes between the Asian powers.

World