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 had Shumilov been in the military when the Soviet invaded Poland? Passage:Colonel (promoted to Major General 4 June 1940) Mikhail Shumilov took command in April 1938. In September 1939, the corps fought in the Soviet invasion of Poland as part of the 10th Army. It included the 6th, 33rd, and the 121st Rifle Divisions at the beginning of the invasion on 17 September. By 2 October, these divisions had transferred to other units, and it included the 29th, 64th, and 145th Rifle Divisions instead. The corps headquarters relocated to Grodno in November and became part of the 11th Army. Between June and July 1940 it was briefly headquartered at Kovno before moving to Siauliai in August, part of the Baltic Special Military District. The 11th transferred to the 8th Army in October, and included the 11th and 125th Rifle Divisions by the outbreak of the war. It defended a 40-kilometer sector on the left flank of the 8th Army, with its headquarters in the forests northwest of Skaudvile. The 125th Rifle Division was in the corps' first echelon, holding covering the highway and railroad from Tilsit to Siauliai. The 48th Rifle Division (part of the adjacent 10th Rifle Corps), after moving forward from Riga, was to take up positions on the left of the 125th. The corps' 73rd Corps Artillery Regiment included four battalions of 107 mm guns.
Links: a. Mikhail Shumilov b. 11th Rifle Division c. 10th Rifle Corps d. Baltic Military District
Example Output: a

Example Input: Question: When was the organization founded to which Cross received appointment as a chevalier? Passage:Colonel Marie Augstin Gaston Cros (known as Gaston Cros) (6 October 1861 10 May 1915) was a French army officer and archaeologist. He was born in Alsace and was displaced when that territory was incorporated into the German Empire. He joined the French Army as a lieutenant and saw action in Tonkin before spending several years surveying in Tunisia, receiving the honours of membership of Vietnamese and Tunisian orders and appointment as a chevalier of the Legion of Honour. In 1901 Cros was appointed head of the French archaeological expedition to Girsu, Iraq to continue the work of Ernest de Sarzec. His work over the next five years included the tracing of the thick city wall and for his work there received a letter of commendation from Gaston Doumergue, the Minister of Fine Arts, and the award of the Golden Palms of the Ordre des Palmes Academiques. Promoted to lieutenant-colonel, Cros served in the French protectorate of Morocco from 1913, seeing action in the Zaian War.
Links: a. Tonkin b. Zaian War c. Ernest de Sarzec d. Legion of Honour
Example Output: d

Example Input: Question: Which noble that Grey served under was born first? Passage:In the Seven Years' War, he served as adjutant in the staff of Duke Ferdinand of Brunswick and on 1 August 1759 was wounded at Minden. On 14 October 1760 he commanded a Light Company at the Battle of Campen, where he was again wounded. One year later, as Lt. Colonel of the 98th Foot, he participated in the Capture of Belle Ile, off the coast of Brittany. Next, he served at the Battle of Havana in 1762. Later, he was on the staff of Wilhelm, Count of Schaumburg-Lippe during the Spanish invasion of Portugal (1762). In 1763 he retired on half-pay, but in 1772 he received a promotion to Colonel and served as aide-de-camp to King George III.
Links: a. Brittany b. George III of the United Kingdom c. Duke Ferdinand of Brunswick-Wolfenbuttel d. Siege of Havana
Example Output:
c