Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: Boris Johnson warned David Cameron last night that he must be prepared to 'walk away' from Europe if he fails to get a good deal for Britain. He used his maiden speech in the Commons since being re-elected as an MP to underline his own Eurosceptic credentials. The London Mayor spelt out a warning to the Prime Minister that Conservative MPs would not accept a cosmetic renegotiation of Britain's membership of the EU. Mr Johnson said he wished the Prime Minister luck on his 'pan-European schmoozathon'. He added: 'I believe his efforts will be crowned with success but I remind him… that if you are going to go into a difficult international negotiation of this kind, then you have to be prepared to walk away if you don't get the result that you want.Mr Johnson said he wished PM luck on his 'pan-European schmoozathon'Said he believed David Cameron's efforts would be 'crowned with success'But said UK should be prepared to 'strike out' and 'forge alternative future' 
 Question:'The Prime Minister has been very clear we are not neutral observers in this – if we can get a decent package we will be selling hard the advantages not just of staying in the _ but of stepping up.

Europe