You will be given a definition of a task first, then some input of the task.
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.

Passage: Northwestern has roughly 225,000 alumni in all branches of business, government, law, science, education, medicine, media, and the performing arts. Among Northwestern's more notable alumni are U.S. Senator and presidential candidate George McGovern, Nobel Prizewinning economist George J. Stigler, Nobel Prizewinning novelist Saul Bellow, Pulitzer Prizewinning composer and diarist Ned Rorem, the much-decorated composer Howard Hanson, Deputy Prime Minister of Turkey Ali Babacan, the historian and novelist Wilma Dykeman, and the founder of the presidential prayer breakfast Abraham Vereide. U.S. Supreme Court Associate Justice John Paul Stevens, Supreme Court Justice and Ambassador to the United Nations Arthur Joseph Goldberg, and Governor of Illinois and Democratic presidential candidate Adlai Stevenson are among the graduates of the Northwestern School of Law. Many Northwestern alumni play or have played important roles in Chicago and Illinois, such as former Illinois governor and convicted felon Rod Blagojevich, Chicago Bulls and Chicago White Sox owner Jerry Reinsdorf, and theater director Mary Zimmerman. Northwestern alumnus David J. Skorton currently serves as president of Cornell University. Rahm Emanuel, the mayor of Chicago and former White House Chief of Staff, earned a Masters in Speech and Communication in 1985.
Output:
Which of Southwestern's alumni is notable for becoming a U.S. Senator and presidential candidate?