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.

Ex Input:
Paragraph- Sent 1: Magnetism is the ability of a material to be attracted by a magnet.
Sent 2: It also include the ability for some material to act like a magnet.
Sent 3: No doubt youve handled refrigerator magnets.
Sent 4: You can see some in Figure 1.28.
Sent 5: You probably know they stick to a metal refrigerator.
Sent 6: This is what holds your homework up.
Sent 7: Maybe your little sisters drawings are hung on the fridge in this manner.
Sent 8: Do magnets stick to all materials?
Sent 9: Of course not.
Sent 10: You have probably checked and they do not stick to other surfaces.
Sent 11: They do not stick to wooden doors or glass windows.
Sent 12: Wood and glass are not attracted to a magnet.
Sent 13: Obviously, only certain materials are attracted to magnets.
Question: Do Magnets stick to all materials? (A) Stick to fridge (B) No (C) Yes (D) Only certain materials are attracted to magnets (E) Magnets stick to all materials.

Ex Output:
B, D.

Ex Input:
Paragraph- Sent 1: Right after the Pentagon was hit, NEADS learned of another possible hijacked aircraft.
Sent 2: It was an aircraft that in fact had not been hijacked at all.
Sent 3: After the second World Trade Center crash, Boston Center managers recognized that both aircraft were transcontinental 767 jetliners that had departed Logan Airport.
Sent 4: Remembering the "we have some planes" remark, Boston Center guessed that Delta 1989 might also be hijacked.
Sent 5: Boston Center called NEADS at 9:41 and identified Delta 1989, a 767 jet that had left Logan Airport for Las Vegas, as a possible hijack.
Sent 6: NEADS warned the FAA's Cleveland Center to watch Delta 1989.
Sent 7: The Command Center and FAA headquarters watched it too.
Sent 8: During the course of the morning, there were multiple erroneous reports of hijacked aircraft.
Sent 9: The report of American 11 heading south was the first; Delta 1989 was the second.
Sent 10: NEADS never lost track of Delta 1989, and even ordered fighter aircraft from Ohio and Michigan to intercept it.
Sent 11: The flight never turned off its transponder.
Sent 12: NEADS soon learned that the aircraft was not hijacked, and tracked Delta 1989 as it reversed course over Toledo, headed east, and landed in Cleveland.
Sent 13: But another aircraft was heading toward Washington, an aircraft about which NORAD had heard nothing: United 93.
Sent 14: United Airlines Flight 93 FAA Awareness.
Sent 15: At 9:27, after having been in the air for 45 minutes, United 93 acknowledged a transmission from the Cleveland Center controller.
Sent 16: This was the last normal contact the FAA had with the flight.
Sent 17: Less than a minute later, the Cleveland controller and the pilots of aircraft in the vicinity heard "a radio transmission of unintelligible sounds of possible screaming or a struggle from an unknown origin."Sent 18: The controller responded, seconds later: "Somebody call Cleveland?"This was followed by a second radio transmission, with sounds of screaming.
Question: Which air traffic center communicated with United 93? (A) Delta (B) Boston Center (C) Cleveland Center (D) Logan Airport (E) Cleveland Center controller (F) Cleveland.

Ex Output:
C, E, F.

Ex Input:
Paragraph- Sent 1: Timothy likes to play sports.
Sent 2: He spends his time after school playing basketball and baseball.
Sent 3: Sometimes Timothy pretends he is a famous baseball pitcher for his favorite team with his friends.
Sent 4: He plays with his friends Mandy and Andrew.
Sent 5: Timothy also plays pretend when he is alone.
Sent 6: He has an imaginary friend named Sean.
Sent 7: Sean is an elephant who watches television with Timothy.
Sent 8: Mandy likes playing baseball but she also likes to paint.
Sent 9: Mandy's favorite class at school is art.
Sent 10: She likes making pictures of flowers.
Sent 11: Her teacher says she is a good artist.
Sent 12: She painted a picture of a tree for her teacher.
Sent 13: There were red and yellow leaves on it.
Sent 14: It had apples on it.
Sent 15: When Andrew goes home after baseball, he likes to eat a snack.
Sent 16: He eats carrots and bananas.
Sent 17: If he is a good boy his mom, Mrs. Smith, sometimes gives him milk and cookies.
Sent 18: Afterwards, Andrew finishes his homework.
Question: What did Mandy paint? (A) Officials (B) Mandy painted flowers and trees.

Ex Output:
B.