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: Did the operation that Musicki contacted the Chetnik leader about actually take place? Passage:Mušicki was stationed in Slavonski Brod at the time of the Axis invasion of Yugoslavia in April 1941 and served as the Royal Yugoslav Army commander responsible for the railroad between Belgrade and Zagreb in the rank of colonel. He demonstrated his support for the Germans by helping their forces during the invasion. Yugoslavia was quickly conquered by the Axis powers and Mušicki remained in Slavonski Brod for several months after the conquest. He attempted to join the Ustaše Militia there, but was rejected. He went to Belgrade in mid-August, where he was received by Zbor leader Dimitrije Ljotić. On 6 October, Milan Nedić, the Prime Minister of the Axis-installed puppet Government of National Salvation, appointed Mušicki to lead the Serbian Volunteer Command (, SDK). Mušicki was involved in executing Serb civilians in the town of Čačak in December 1941. He and Milan Aćimović contacted Chetnik leader Draža Mihailović on 5 December, possibly in an effort to warn him in advance of the assault the Germans had planned, codenamed Operation Mihailovic. This action prompted the Germans to question Mušicki's loyalty. He was removed from command at the end of 1941 and imprisoned by the Germans, but was later freed at Nedić's intervention.
 Links: a. Royal Yugoslav Army b. Operation Mihailovic c. Dimitrije Ljotić d. Government of National Salvation
Example Output: b

Example Input: Question: Who ruled the Seljuk Empire when they annexed Taşburun? Passage:According to mayor's page Taşburun was founded by Turkmen tribe named Taşburun after Seljuks annexed the area to their realm in 1064. In 1239 it was captured by the Mongols and in 1514 by the Ottoman Empire. It was ceded to Safavid Persia by the Treaty of Istanbul (1736) . In 1746 it was returned to Ottoman Empire by the Treaty of Kerden but lost to Russian Empire by the Treaty of San Stefano signed after the Russo-Turkish War (1877–1878). At the end of the First World War it was returned to Turkey. In 1993 it was declared a seat of township.
 Links: a. World War I b. Ottoman Empire c. Treaty of San Stefano d. Seljuq dynasty
Example Output: d

Example Input: Question: How long did the advance across the Seine last? Passage:The division arrived in Liverpool on April 17 and began training in amphibious operations. After training in the United Kingdom from 17 April 1944, the 79th Infantry Division landed on Utah Beach, Normandy, 12–14 June and entered combat 19 June 1944, with an attack on the high ground west and northwest of Valognes and high ground south of Cherbourg. The division took Fort du Roule after a heavy engagement and entered Cherbourg, 25 June. It was around this time that Corporal John D. Kelly and First Lieutenant Carlos C. Ogden, both of the 314th Infantry Regiment, were awarded the Medal of Honor. It held a defensive line at the Ollonde River until 2 July 1944 and then returned to the offensive, taking La Haye du Puits in house-to-house fighting, 8 July. On 26 July, the 79th attacked across the Ay River, took Lessay, crossed the Sarthe River and entered Le Mans, 8 August, meeting only light resistance. The advance continued across the Seine, 19 August. Heavy German counterattacks were repelled, 22–27 August, and the division reached the Therain River, 31 August. Moving swiftly to the Franco-Belgian frontier near St. Amand (east of Lille), the division was then moved to XV Corps in eastern France, where it encountered heavy resistance in taking Charmes in street fighting, 12 September. The 79th cut across the Moselle and Meurthe Rivers, 13–23 September, cleared the Forêt de Parroy in a severe engagement, 28 September–9 October, and attacked to gain high ground east of Emberménil, 14–23 October, when it was relieved, 24 October.
 Links: a. Cherbourg-Octeville b. Le Mans c. Utah Beach d. Seine River Crossing at Mantes-Gassicourt
Example Output:
d