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 long did the state entity that  Macedonia was the political heart of  last? Passage:In 1014, after decades of war, the Byzantine Emperor Basil II scored a decisive victory over the Bulgarian Emperor Samuil in the battle of Kleidion. Samuil died of a heart attack on 6 October 1014 and the Byzantines took the opportunity to penetrate deep into Macedonia, the political heart of the Bulgarian Empire, and seized a number of important cities (Bitola, Prilep, Voden, Maglen). After the new Bulgarian Emperor Ivan Vladislav, who in 1015 assassinated Samuil's son and heir Gavril Radomir, had unsuccessfully tried to make an agreement with Basil II, he organized the defense of the country. The Bulgarians led by the Emperor, Krakra of Pernik and Ivats managed to return a number of towns and castles. The Byzantines were defeated in the battle of Bitola (September 1015) and at the siege of Pernik (summer of 1016).
 Links: a. Basil II b. Ivan Vladislav of Bulgaria c. First Bulgarian Empire d. Prilep
Example Output: c

Example Input: Question: How old was Warren Harding the year Coolidge was born? Passage:Calvin Coolidge (born John Calvin Coolidge Jr.; ; July 4, 1872 – January 5, 1933) was an American politician and lawyer who served as the 30th president of the United States from 1923 to 1929. A Republican lawyer from New England, born in Vermont, Coolidge worked his way up the ladder of Massachusetts state politics, eventually becoming governor of Massachusetts. His response to the Boston Police Strike of 1919 thrust him into the national spotlight and gave him a reputation as a man of decisive action. The next year, he was elected vice president of the United States, and he succeeded to the presidency upon the sudden death of Warren G. Harding in 1923. Elected in his own right in 1924, he gained a reputation as a small government conservative and also as a man who said very little and had a rather dry sense of humor.
 Links: a. Vice President of the United States b. Politics c. Boston Police Strike d. Warren G. Harding
Example Output: d

Example Input: Question: Are the writers that Horiguchi studied while in Belgium both French? Passage:In 1911, Horiguchi left school to accompany his father on overseas postings and during the next 14 years overseas he became fluent in French (assisted by his Belgian stepmother) and interested in French literature, particularly the novels and poetry of the Symbolist movement. He first spent over a year in Mexico, where he was diagnosed with tuberculosis, causing Horiguchi to abandon his father's hope that he become a diplomat, and he devoted his time to writing verse and translation of French works instead. He was in Mexico during the Mexican Revolution, and it was also during this time that he was drawn to Parnassianism as a style of verse. In 1913, the family relocated to Belgium, via Siberia. While in Belgium, he studied the works of Paul Verlaine and the works of the Symbolist movement, including the works of Remy de Gourmont. He subsequently lived for brief periods in Spain, Paris, Brazil and Romania and maintained correspondence with Marie Laurencin and Thomas Mann, whose works he also translated while recuperating at a sanatorium in Switzerland.
 Links: a. Mexican Revolution b. Paul Verlaine c. Symbolism (arts) d. Parnassianism
Example Output:
b