You will be given a definition of a task first, then some input of the task.
This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Passage: There are 366 railway stations in the London Travelcard Zones on an extensive above-ground suburban railway network. South London, particularly, has a high concentration of railways as it has fewer Underground lines. Most rail lines terminate around the centre of London, running into eighteen terminal stations, with the exception of the Thameslink trains connecting Bedford in the north and Brighton in the south via Luton and Gatwick airports. London has Britain's busiest station by number of passengers Waterloo, with over 184 million people using the interchange station complex (which includes Waterloo East station) each year. Clapham Junction is the busiest station in Europe by the number of trains passing. Question: What is Europe's busiest rail station in terms of train activity?
Output:
Clapham Junction