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: Are the two canals which were built in 1914 and 1930, and which are located in parallel to the Lippe, of equal length to each other? Passage:Historically, the preconditions for a change of the landscape started with the construction of the Cologne-Minden trunk line in the 1840s that connected the river Rhine settlements like Cologne with harbours and trade at the river Weser and so with the Lippe town Hamm, too. Moreover, this railway supported the coal and steel industry development in the northern Ruhr region. The hard coal mining that started in the middle of the 19th century in the Emscher catchment area developed in the following decades direction north and so to the Lippe catchment area, too, where from the 1860s on first problems from mining subsidence and drainage of polluted water appeared. The historical city of Hamm and the towns Lunen, Haltern and Dorsten were small settlements located at the Lippe but expanded with the establishing of hard coal mines starting around 1900. The industrialization caused huge water quality problems in the Lippe tributaries and the Lippe itself; therefore first in 1913 the Sesekegenossenschaft and later in 1926 the Lippeverband as water boards ("Wasserwirtschaftsverbande") were established. Since 1914 the Datteln-Hamm Canal and 1930 the Wesel-Datteln Canal are located in parallel to the Lippe which is not navigable for mass transportation. The canals receive Lippe water or feed the Lippe (to improve dry weather flow) from an exchange facility in Hamm, operated by the Wasserverband Westdeutsche Kanale.
Links: a. Cologne-Minden trunk line b. Wasserverband Westdeutsche Kanale c. Datteln-Hamm Canal d. Weser
Example Output: c

Example Input: Question: Which Nigerian region that saw their teams' promotion to the Premier League has the largest population? Passage:The 2018 Nigeria Women Premier League began on April 7 in a game featuring defending champions Nasarawa Amazons from Nasarawa State and FC Robo of Lagos State. The date was decided following a congress held in Ikeja on March 3. Prior to the game, a maiden super cup named the NWFL Champions Shield match was played between Aiteo Cup winners, Rivers Angels and Nasarawa Amazons to officially open the new season. At the end of the 2017 season, Sure Babes of Ilorin, Jokodolu Babes of Ogbomosho and Taraba Queens of Taraba State were promoted to compete in the elite division pending registration procedures, while Saadatu Amazons of Minna and Heartland Queens of Owerri were relegated to the pro league. In May 2018, the league went on a mid-season break due to the 2018 FIFA World Cup, this was further elongated after an emerging NFF leadership crisis. In August 2018, it was announced that the remaining games of the league will commence September 12.
Links: a. Nasarawa Amazons b. Ilorin c. 2018 FIFA World Cup d. Ilorin
Example Output: b

Example Input: Question: What was the name of Telfer's maternal grandfather? Passage:The son of Margaret Mellis and Adrian Stokes, he was born in St Ives and studied at the Slade School of Fine Art. He pursued postgraduate studies at the Brooklyn Museum Art School after being awarded a Beckmann Fellowship. He taught at Reading Art School and the Bath Academy in Corsham and exhibited his paintings in London, including a show at the Serpentine Gallery. In 1971, Stokes founded publishing firm Weproductions, which produced artist's books; from 1974, he operated in partnership with Helen Douglas. In 2002, Stokes moved to East Anglia to care for his mother. He redirected his focus to sculpture, which he exhibited at the Kettle's Yard open house in 2008 and at shows in various galleries.
Links: a. Brooklyn Museum Art School b. Margaret Mellis c. Kettle's Yard d. Adrian Stokes (critic)
Example Output:
b