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: On what date did Apollo 11 land at it's destination site? Passage: are three views of Mare Tranquillitatis on the Moon, taken by the mapping camera of the Apollo 17 mission in 1972, facing south-southwest from an average altitude of 111km on Revolution 36 of the mission. At the left is the east side of Mare Tranquillitatis, with the craters Franz (bottom right), Lyell (dark floor, right of center), and Taruntius (upper left). The "bay" of dark mare (basalt) at left is Sinus Concordiae, with "islands" of older, light highland material. At the right is the crater Cauchy, which lies between the Rupes Cauchy and Cauchy rille. The center photo shows the central mare with craters Vitruvius (lower right) and Gardner (bottom center). At the horizon are lighter highlands at the southern margin of the mare, near the Apollo 11 landing site. The crater Jansen is visible at the edges of both the center and right photos. The right photo shows the western mare, with the craters Dawes (lower left) and the large Plinius (43km diameter), with the Plinius Rilles in the foreground. These photos were taken within minutes of each other as the command module America orbited the Moon. The Sun elevation drops from 46 degrees at left to 30 degrees at right.
Links: a. Apollo 11 b. Apollo 17 c. Lyell (lunar crater) d. Plinius (crater)
Example Output: a

Example Input: Question: Who won the World Cup where the Costa Rican team had a prominent performance? Passage:Since the late 1980s, the team has continuously been visible as a solidly competitive side, with a prominent performance in the 1990 FIFA World Cup in Italy, making it to the knockout stage in their debut after finishing second in their group during the first phase, below Brazil. They also managed to qualify for the 2002 and 2006 FIFA World Cups. In 2014, Costa Rica made their best performance in history by finishing first in their group that consisted of three former World Cup champions: Uruguay, Italy, and England. During the Round of 16 they defeated Greece 53 via a penalty shootout after a 11 draw. Moreover, during the match against a much better team, Navas saved more than 15 shots due to the Costa Rican very weak defense. The match was characterized as "Navas vs Greece". They reached the quarterfinals for the very first time as the Ticos were defeated by the Netherlands also in a penalty shootout (34) after a scoreless draw on 5 July. Their 2018 World Cup campaign ended in a 4th place group stage exit with their only point coming from a 2-2 draw vs Switzerland.
Links: a. 2006 FIFA World Cup b. 1990 FIFA World Cup c. 2006 FIFA World Cup d. Keylor Navas
Example Output: b

Example Input: Question: What years did Cyrus the Great rule the Achaemenid Empire? Passage:Iran is home to one of the world's oldest continuous major civilizations, with historical and urban settlements dating back to 7000 BC. The south-western and western part of the Iranian Plateau participated in the traditional Ancient Near East with Elam, from the Early Bronze Age, and later with various other peoples, such as the Kassites, Mannaeans, and Gutians. Georg Wilhelm Friedrich Hegel calls the Persians the "first Historical People". The Medes unified Iran as a nation and empire in 625 BC. The Achaemenid Empire (550330 BC), founded by Cyrus the Great, was the first true global superpower state and it ruled from the Balkans to North Africa and also Central Asia, spanning three continents, from their seat of power in Persis (Persepolis). It was the largest empire yet seen and the first world empire. The Achaemenid Empire was the only civilization in all of history to connect over 40% of the global population, accounting for approximately 49.4 million of the world's 112.4 million people in around 480 BC. They were succeeded by the Seleucid, Parthian, and Sasanian Empires, who successively governed Iran for almost 1,000 years and made Iran once again as a leading power in the world. Persia's arch-rival was the Roman Empire and its successor, the Byzantine Empire.
Links: a. Kassites b. Achaemenid Empire c. Persepolis d. Iranian Plateau
Example Output:
b