Detailed Instructions: This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
Problem:Passage: Much of YouTube's revenue goes to the copyright holders of the videos. In 2010 it was reported that nearly a third of the videos with advertisements were uploaded without permission of the copyright holders. YouTube gives an option for copyright holders to locate and remove their videos or to have them continue running for revenue. In May 2013, Nintendo began enforcing its copyright ownership and claiming the advertising revenue from video creators who posted screenshots of its games. In February 2015, Nintendo agreed to share the revenue with the video creators.
Solution:
What did Nintendo start enforcing in 2015?