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: How old was the commander in chief when he coordinated a massive anti-guerrilla operation? Passage:In 1970, 22-year-old Crespo had dropped out of IST and was eventually drafted into military service in the Portuguese Colonial War. He transferred to Mozambique where his military occupation was to check the cement cargoes from Beira to the Cahora Bassa Dam construction site, near Tete. Some time later, due to his good fluency in English, he was placed in the press office of Kaúlza de Arriaga, the commander in chief of the Portuguese Armed Forces in Mozambique, who had coordinated a massive anti-guerrilla operation against FRELIMO separatists in 1970 - the Gordian Knot Operation. While serving in the army, Crespo also entered the newly created School of Medicine of the University of Lourenço Marques where he would complete a number of academic disciplines but did not graduate. He also married Helen de Souza from Johannesburg, a South African woman with Portuguese ancestry who worked in genetics. After the Carnation Revolution left-leaning military coup at Lisbon in April 1974, fresh out of the troop, Crespo fled Mozambique for South Africa.
 Links: a. Portuguese Colonial War b. Tete, Mozambique c. Kaúlza de Arriaga d. Kaúlza de Arriaga
Example Output: c

Example Input: Question: Which of Messner's teachers at the University of Munich was older? Passage:After Meissner’s abitur at the Humanistisches Gymnasium, in 1910, he began the study of physics and mathematics at University of Tübingen. After three terms, he went to the University of Munich as a student of the experimentalist Wilhelm Röntgen and the theoretician Arnold Sommerfeld. After one year at Munich, he returned to Tübingen to be able to study spectroscopy with Friedrich Paschen. While still a student in 1914, Meissner was able to prove the existence of oxygen lines in the solar spectrum. He was awarded his doctorate in 1915, on a thesis with the title Interferometrische Wellenlängenbestimmung im infraroten Spektralbereich. In 1916 he became an assistant to Edgar Meyer at the University of Zurich, under whom he completed his Habilitation, in 1918, with the Habilitationsschrift title Untersuchungen des Neonspektrums. The following year, he married the Polish physicist Doctor Janka Kohn.
 Links: a. Habilitation b. Ludwig Maximilian University of Munich c. University of Tübingen d. Wilhelm Röntgen
Example Output: d

Example Input: Question: How many laps around the Olympic track did Kifle make while running heats in his Olympic debut? Passage:Kifle was born in Adi Billai in Eritrea's Debub Region. He made his first international appearance for Eritrea at the age of 21, running in the 3000 metres at the 1999 IAAF World Indoor Championships. He finished in last place and was over twenty seconds behind the rest of the runners. His first international outdoor competition followed later that year and he ran in the heats of the 5000 metres at the 1999 World Championships in Athletics in Seville. In 2000 he came 61st at the 2000 IAAF World Cross Country Championships and made his Olympic debut with a performance in the heats of the 10,000 metres at the 2000 Sydney Olympics. He began to improve from the 2002 season onwards: he was eighth in the long race at the 2000 IAAF World Cross Country Championships, fourth at the 2002 IAAF World Half Marathon Championships with a time of 1:01:05 hours, and came sixth over 5000 m at the 2002 African Championships in Athletics. He also won the Cursa de Bombers 10K in Spain that year.
 Links: a. 2000 IAAF World Cross Country Championships b. 10,000 metres c. 2000 IAAF World Cross Country Championships d. 2000 IAAF World Cross Country Championships
Example Output:
b