In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.

Input: Consider Input: Question: What golf course did Romero win his first senior title? Passage:Romero first played on the European Tour in 1985 and was a full member from 1988 to 2005. He has 8 tournament victories and seven top twenty placings on the Order of Merit. In 2002 he became the third oldest winner on the European Tour (behind Des Smyth and Neil Coles) when he won the Scottish Open just three days before his 48th birthday. Romero came fifth on the Order of Merit for 2002. Romero turned fifty in 2004, and just a few days later he finished in a tie for second at his first senior tournament, the Senior British Open. In 2005 he won his first senior title at the European Seniors Tour's Travis Perkins Senior Masters, and he won the Wentworth Senior Masters in both 2005 and 2006. In 2006, he lost in a playoff against Loren Roberts for the Senior British Open Championship and won a playoff against Lonnie Nielsen for the JELD-WEN Tradition for his first Champions Tour win and major. He was the Champions Tour's 2006 Rookie of the Year. He won the U.S. Senior Open, his second major, at The Broadmoor in Colorado Springs in 2008.
 Links: a. Senior Open Championship b. Wentworth Senior Masters c. PGA Tour Champions d. Lonnie Nielsen

Output: b


Input: Consider Input: Question: How many people died in the incident that contaminated about 30,000 km?  Passage:Natural strontium is a mixture of four stable isotopes: Sr, Sr, Sr, and Sr. Their abundance increases with increasing mass number and the heaviest, Sr, makes up about 82.6% of all natural strontium, though the abundance varies due to the production of radiogenic Sr as the daughter of long-lived beta-decaying Rb. Of the unstable isotopes, the primary decay mode of the isotopes lighter than Sr is electron capture or positron emission to isotopes of rubidium, and that of the isotopes heavier than Sr is electron emission to isotopes of yttrium. Of special note are Sr and Sr. The former has a half-life of 50.6 days and is used to treat bone cancer due to strontium's chemical similarity and hence ability to replace calcium. While Sr (half-life 28.90 years) has been used similarly, it is also an isotope of concern in fallout from nuclear weapons and nuclear accidents due to its production as a fission product. Its presence in bones can cause bone cancer, cancer of nearby tissues, and leukemia. The 1986 Chernobyl nuclear accident contaminated about 30,000 km with greater than 10 kBq/m with Sr, which accounts for 5% of the core inventory of Sr.
 Links: a. Rubidium b. Mass number c. Electron capture d. Chernobyl disaster

Output: d


Input: Consider Input: Question: How many championships did the team that Fairbanks's 1970 team tie in the  Bluebonnet Bowl  win? Passage:Fairbanks lost four games in each of the next three seasons. Despite the relatively mediocre record of those years, several great players came through Fairbanks's program. One of those players was Steve Owens. After an impressive year in 1969, despite Oklahoma's 6–4 record, Owens was named the Sooners' second Heisman Trophy winner. It did not take long for Fairbanks to return the team to form. He and his offensive co-ordinator Barry Switzer helped implement the use of the wishbone offense. Fairbanks' 1970 team tied Bear Bryant's Alabama Crimson Tide in the Bluebonnet Bowl to finish the season ranked #20. They began the 1971 season ranked number ten. In consecutive weeks, they beat #17 USC, #3 Texas and #6 Colorado. These early-season wins propelled them to a #2 national ranking and set the stage for one of the great college football games of the century against top-ranked Nebraska. Led by quarterback Jack Mildren and running back Greg Pruitt, Oklahoma was a scoring machine, averaging 44.5 points per game, the second highest in team history. The offense set the all-time NCAA single-season rushing record at 472.4 yards per game, a record which still stands to this day. Equally impressive that season was Pruitt's nine yards per carry, and Mildren is often referred to as "the Godfather of the wishbone" by University of Oklahoma football fans. On November 25, 1971, Nebraska edged Oklahoma, 35–31 in the Game of the Century what was to be the only loss of the season for Oklahoma. Oklahoma went on to beat Oklahoma State and fifth ranked Auburn to finish the season ranked number two. Fairbanks closed out his career at Oklahoma the following year with a win in the Sugar Bowl over Penn State after having lost once all season, to Colorado. Following this season, Fairbanks accepted a position with the NFL's New England Patriots.
 Links: a. 1971 Auburn Tigers football team b. 1970 Alabama Crimson Tide football team c. 1972 Penn State Nittany Lions football team d. 1971 USC Trojans football team


Output: b