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.

Example Input: Question: When was the facility where Bill Clinton and his Vice-President had lunch after a ceremony on the banks of the scenic New River built? Passage:Ashe County has been home to, produced, or been visited by, several prominent people. It is the hometown of Monte Weaver from Helton who pitched for the Washington Senators and pitched a World Series game in 1933. After being traded from the Senators, he pitched for the Boston Red Sox, before being called into service in World War II. Weaver died in 1994. Albert Hash a well-known and beloved fiddler and instrument maker at one time resided in Lansing. Helen Keller visited an Ashe County native, Marvin Osborne, in 1944 when he was wounded in France in World War II. Loretta Lynn sang at the Central Food Market in West Jefferson in the late 1960s (the Central Food building formally housed a locally owned auto parts store and is now the location of a local restaurant). Roni Stoneman was a visitor to Ashe Park in the 1980s. In 1998, then-President Bill Clinton and his Vice-President, Al Gore, held a ceremony on the banks of the scenic New River to designate it as an American Heritage River. After the ceremony, both men had lunch at the historic Glendale Springs Inn, also located in Ashe County. Fiddle player G. B. Grayson was born in Ashe County in 1887.
Links: a. World Series b. Glendale Springs Inn c. American Heritage Rivers d. Helen Keller
Example Output: b

Example Input: Question: How old was Waledynski when the autocephaly he requested was finally granted? Passage:The establishment of the church was undertaken after the Treaty of Riga left a large amount of territory previously under the control of the Russian Empire, as part of the Second Polish Republic. Eastern Orthodoxy was widespread in the Belarusian Western Belarus regions and the Ukrainian Volhynia. The loss of ecclesiastical link due to the persecution of the Russian Orthodox Church in the Soviet Union, left the regional clergy in a crisis moment, and in 1924, the Ecumenical Patriarchate took over establishing several autonomous churches on territories of the new states that were formerly wholly or partially part of the Russian Empire (Finland, the Baltic States, and Poland). Earlier, in January 1922, the Polish government had issued an order recognizing the Orthodox church and placing it under the authority of the state. At that time a Ukrainian, Yurii Yaroshevsky, was appointed Metropolitan and exarch by the patriarch of Moscow. When Yaroshevsky began to reject the authority of Moscow Patriarchate, he was assassinated by a Russian monk. Nonetheless, his successor, Dionizy Waledynski (Dionisii Valedinsky), continued to work for the autocephaly of the Polish Orthodox church, which was finally granted by the Ecumenical Patriarch of Constantinople in his Tomos of 13 November 1924. Given that most of the parishioners were Ukrainians and Belarusians living in the Eastern areas of the newly independent Polish Second Republic, the Patriarch of Constantinople had a canonical basis to grant the Tomos to the Polish church as a successor of the Kyiv Metropolia, the former territory of Kyivan Rus' which Constantinople continued to see as its canonical territory (despite having agreed to allow Moscow to be its caretaker it in 1686). The Russian Orthodox Church at the time did not recognise the Polish autocephaly, as it did not recognise the autocephaly of the Orthodox Church of the Czech Lands and Slovakia.
Links: a. Second Polish Republic b. 2018 MoscowConstantinople schism c. Ecumenical Patriarchate of Constantinople d. Dionizy (Waledynski)
Example Output: d

Example Input: Question: What year did construction begin on the dam that the river passes through before Afterbay Dam? Passage:The Bighorn River begins as the Wind River in the Rocky Mountains at Wind River Lake, near Two Ocean Mountain and the summit of Togwotee Pass. The Wind River flows southeast receiving the east fork of the Wind River from the north, and enters the Wind River Basin, flowing past Dubois and Johnstown, to Riverton, where it receives the Little Wind River. The river then changes direction to the northeast and then the north, flowing into Boysen Reservoir, which is formed by Boysen Dam. Below the dam it enters the Wind River Canyon, where the river narrows and forms many rapids. At the end of the canyon the Wind River widens out in an area called the Wedding of the Waters where it becomes the Bighorn River and enters the Bighorn Basin. The Bighorn continues northward, passing through Thermopolis, Worland, and Basin. At Greybull it receives the Greybull River, and about north of that confluence it enters Bighorn Lake, where it is joined by the Shoshone River. North of the confluence with the Shoshone, the reservoir narrows as the river enters the Bighorn Canyon, where it crosses into Montana. At the end of the canyon, the river passes through Yellowtail Dam and Afterbay Dam. The river turns to the northeast and enters the Great Plains. At Hardin the river is joined by the Little Bighorn River. Approximately downriver from the Little Bighorn, in Big Horn County, the Bighorn empties into the Yellowstone.
Links: a. Bighorn Lake b. Boysen Dam c. Yellowtail Dam d. Bighorn Canyon National Recreation Area
Example Output:
c