Given the task definition and input, reply with output. 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. Among the entities, try to find the best entity that is most likely to fill in "_" and classify the answers based on options.

Republican presidential frontrunner Donald Trump said it was not his job to stand up for U.S. President Barack Obama after a man at one of his campaign events said he was a Muslim and 'not even an American.' 'Am I morally obligated to defend the president every time somebody says something bad or controversial about him? I don't think so!' Trump said on Twitter on Saturday morning. Trump drew criticism on Friday from Republican and Democratic rivals in the 2016 race for the presidency when he failed to challenge a man at a New Hampshire town hall Thursday night who said Muslims were a problem in the United States.Donald Trump wrote on Twitter saying he's not morally obligated to defend President Obama every time someone makes controversial commentHe said if someone made a nasty comment about him to Obama there's 'no chance' the president would come to his rescueOn Thursday, Trump failed to correct a man at one of his campaign events who said Obama is a Muslim and 'not even an American' 
 Questions:_'s campaign manager later said that Trump had had trouble hearing in the busy room. (A) Republican (B) Donald Trump (C) U.S. (D) Barack Obama (E) Muslim (F) American (G) Twitter (H) Democratic (I) New Hampshire (J) Muslims (K) United States (L) Obama

(B)