You are given a paragraph, a question and some answer options (associated with "A", "B", "C", "D", etc.) You need to list all the correct answer options with their associated letters (e.g. "A" can be a valid answer). Note that sometimes, more than one option can answer the question correctly and completely. In those cases, please generate all such options separated by a comma (e.g. "A, B" is a valid answer). Do not generate anything else apart from one or more of the following characters: 'A', 'B, 'C', 'D', etc.

Example Input: Paragraph- Sent 1: Soon after the conclusion of peace, important changes were made in legislation concerning industry and commerce, and the new freedom thus afforded produced a large number of limited liability companies.
Sent 2: Plans were formed for building a great network of railways, partly for the purpose of developing the natural resources of the country, and partly for the purpose of increasing its power for defense and attack.
Sent 3: The existence of serfdom was tackled boldly, taking advantage of a petition presented by the Polish landed proprietors of the Lithuanian provinces and, hoping that their relations with the serfs might be regulated in a more satisfactory way (meaning in a way more satisfactory for the proprietors), he authorized the formation of committees "for ameliorating the condition of the peasants," and laid down the principles on which the amelioration was to be effected.
Sent 4: This step had been followed by one even more significant.
Sent 5: Without consulting his ordinary advisers, Alexander ordered the Minister of the Interior to send a circular to the provincial governors of European Russia (serfdom was rare in other parts), containing a copy of the instructions forwarded to the Governor-General of Lithuania, praising the supposed generous, patriotic intentions of the Lithuanian landed proprietors, and suggesting that perhaps the landed proprietors of other provinces might express a similar desire.
Sent 6: The hint was taken: in all provinces where serfdom existed, emancipation committees were formed.
Sent 7: The emancipation was not merely a humanitarian question capable of being solved instantaneously by imperial ukase.
Sent 8: It contained very complicated problems, deeply affecting the economic, social and political future of the nation.
Sent 9: Alexander had to choose between the different measures recommended to him and decide if the serfs would become agricultural laborers dependent economically and administratively on the landlords or if the serfs would be transformed into a class of independent communal proprietors.
Sent 10: The emperor gave his support to the latter project, and the Russian peasantry became one of the last groups of peasants in Europe to shake off serfdom.
Sent 11: The architects of the emancipation manifesto were Alexander's brother Konstantin, Yakov Rostovtsev, and Nikolay Milyutin.
Sent 12: On 3 March 1861, 6 years after his accession, the emancipation law was signed and published.
Question: When was the existence of serfdom tackled? (A) 6 years after his accession (B) Soon after the conclusion of peace (C) In March, 1931.
Example Output: B.

Example Input: Paragraph- Sent 1: The city of Edinburgh grew up around the steep, ragged cliff of the Castle Rock and its easily defended summit.
Sent 2: Archaeological excavations have revealed evidence of habitation here as long ago as 900 b.c.
Sent 3: Very little, however, is known about the Rock and its inhabitants in the centuries between its first occupation and the time of the MacAlpin kings.
Sent 4: A few shadowy details have been left to us by the Romans and by an epic poem from the seventh century.
Sent 5: Romans and Britons The Romans invaded Scotland in a.d.
Sent 6: 7884, where they met a fierce group called the Picts, whom they drove north.
Sent 7: They consolidated their gains by building Antonine's Wall across the waist of Scotland between the Firth of Forth and the River Clyde in about a.d.
Sent 8: Roman legions encountered the strongholds of the Castle Rock and Arthur's Seat, held by a tribe of ancient Britons known as the Votadini.
Sent 9: Little is recorded about this group, but they were probably the ancestors of the Gododdin, whose feats are told in a seventh-century Old Welsh manuscript.
Sent 10: The capital of the Gododdin was Din Eidyn (the "Fort of Eidyn," almost certainly the Castle Rock), whose name lives on in the Edin- of Edinburgh.
Sent 11: Din Eidyn fell to the Angles in 638 and became part of the Anglian kingdom of Northumbria.
Sent 12: It was the first of many times that the Fort of Eidyn would change hands between the kingdoms of the north and the south.
Sent 13: The MacAlpin Kings Four distinct peoples once inhabited the land now known as Scotland: the Picts in the north, the Britons in the southwest, the invading Angles in the southeast, and the Scots in the west.
Sent 14: The Scots were Gaelic-speaking immigrants from the north of Ireland.
Sent 15: Kenneth MacAlpin, who ruled as king of Scots at Dunadd, acquired the Pictish throne in 843, uniting Scotland north of the River Forth into a single kingdom.
Sent 16: He moved his capitalalong with the Stone of Destiny (on which Scottish kings were crowned)to the sacred Pict site of Scone, close to Perth.
Sent 17: His great-great-great-grandson, Malcolm II (10051034), defeated the Angles at the Battle of Carham in 1018 and extended Scottish territory as far south as the River Tweed.
Question: When the Romans invaded Scotland in A.D. 78-84, which group did they drive out? (A) Scone (B) Scotts (C) The Scots (D) The Picts (E) The Britons (F) The Votadini.
Example Output: D.

Example Input: Paragraph- Sent 1: Speed is an important aspect of motion.
Sent 2: It is a measure of how fast or slow something moves.
Sent 3: To determine speed you must know two things.
Sent 4: First, you must know how far something travels.
Sent 5: Second, you need to know how long it takes to travel that far.
Sent 6: Speed can be calculated using this formula: speed = distance time A familiar example is the speed of a car.
Sent 7: In the U.S., this is usually expressed in miles per hour.
Sent 8: Think about a trip you and your family made in the car.
Sent 9: Maybe the trip covered 120 miles and it took 3 hours.
Sent 10: What was the cars speed?
Sent 11: speed = 120 mi = 40 mi/h 3h The speed of a car may also be expressed in kilometers per hour (km/h).
Sent 12: The SI unit for speed is meters per second (m/s).
Sent 13: This is the unit of measure a scientist would use.
Question: What is speed? (A) How long it takes to travel that far (B) Speed is an important aspect of motion (C) The measure of gravity against time (D) It is a measure of how far something is (E) Gravitational pull (F) When something moves (G) A force of gravity (H) How far something travels (I) An aspect of motion, it is the measure of how slow or fast something travels (J) How quick something moves in space (K) It is a measure of how fast or slow something moves (L) A measure of how fast or slow something moves (M) The measure of motion (N) An aspect of motion; a measure of how fast or slow an object moves.
Example Output:
B, I, K, L, N.