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: Crew members ran for their lives when overhanging metalwork crashed onto a stage in a Toronto park Saturday afternoon, pinning and killing one man, authorities said.
Sent 2: The collapse happened around 4 p.m., one hour before spectators were set to begin streaming in for a concert by the alternative rock group Radiohead.
Sent 3: Several people were on the stage at the time, preparing for the show, when scaffolding-like material towering about 50 feet above collapsed.
Sent 4: "Unfortunately, four people were hurt," Toronto police Constable Tony Vella said.
Sent 5: "The remainder of the people, when they heard the stage coming (down), ran from the area."Sent 6: Firefighters arrived to find one man "trapped under the structure," said Toronto fire Platoon Chief Tony Bellavance.
Sent 7: They helped to extricate the man, then moved away from what was then still considered an "unstable structure," Bellavance added.
Sent 8: Paramedics, who happened to be at the scene in preparation for the concert, "immediately rendered aid," according to on-site Toronto Emergency Medical Services commander Peter Rotolo.
Sent 9: The victim -- who has not been identified, amid efforts to contact his next of kin -- was pronounced dead at the scene.
Sent 10: Police said he was in his 30s.
Sent 11: Another man who suffered serious injuries due to the collapse was transported to Toronto's Sunnybrook Hospital, Ian McClelland of the city's EMS department said.
Sent 12: The 45-year-old man suffered a head injury that isn't considered life-threatening, according to Toronto police.
Sent 13: Two other men with minor injuries were assessed and released, McClelland said.
Sent 14: Aerial footage afterward showed that some metal framing -- some of it covered in a blue material -- crumpled on the stage, which was in front of a large grassy area.
Sent 15: Some of the scaffolding-like material remained standing, reaching about 50 feet in the sky.
Sent 16: The stage was being set up especially for the Radiohead concert, Vella said.
Sent 17: At the time it came down, the weather was good with no storm rolling through or significant winds, added fellow police Constable Harrison Ford.
Question: Who "immediately rendered aid" when overhanging metalwork crashed onto a stage in a Toronto park Saturday afternoon? (A) Mobile command unit members (B) Emergency medical services (C) Paramedics who happened to be at the scene (D) Parmedics (E) Firefighters (F) Paramedics.
Example Output: C, D, F.

Example Input: Paragraph- Sent 1: These incoherent words threw the first glimpse of light on the meaning of her distress and penitence.
Sent 2: I doubt if the best woman in Christendom would so reproach and abase herself, if convicted of even a worse sin than the secret use of those stimulants for which the "charny" is a Martial equivalent.
Sent 3: No Martialist would dream of poisoning his blood and besotting his brain with alcohol in any form.
Sent 4: But their opiates affect a race addicted to physical repose, to sensuous enjoyment rather than to sensual excitement, and to lucid intellectual contemplation, with a sense of serene delight as supremely delicious to their temperament as the dreamy illusions of haschisch to the Turk, the fierce frenzy of bhang to the Malay, or the wild excitement of brandy or Geneva to the races of Northern Europe.
Sent 5: But as with the luxury of intoxication in Europe, so in Mars indulgence in these drugs, freely permitted to the one sex, is strictly forbidden by opinion and domestic rule to the other.
Sent 6: A lady discovered in the use of "charny" is as deeply disgraced as an European matron detected in the secret enjoyment of spirits and cigars; and her lord and master takes care to render her sufficiently conscious of her fault.
Question: How does she feel about taking the drug? (A) Good (B) Guilty (C) Bad (D) Distressed, penitent and disgraced (E) Happy.
Example Output: B, D.

Example Input: Paragraph- Sent 1: You know that friction also causes heat.
Sent 2: Think about when you rub your hands together.
Sent 3: It is friction that makes them warm.
Sent 4: But why does this happen?
Sent 5: Friction causes the molecules on rubbing surfaces to move faster.
Sent 6: Faster moving particles have more heat energy.
Sent 7: Heat from friction can be useful.
Sent 8: Can you think of other places where you might find friction?
Sent 9: Friction also lets you light a match.
Sent 10: Heat from friction can also cause problems.
Sent 11: It can cause a car to overheat.
Sent 12: To reduce friction, oil is added to the engine.
Sent 13: Oil coats the surfaces of moving parts.
Sent 14: This coating of oil makes them slippery.
Sent 15: When things are slippery there is less friction.
Sent 16: Have you ever seen a sign that says, slippery when wet?
Sent 17: This too has to do with friction.
Sent 18: Water, like oil, can reduce friction.
Sent 19: The wet surface may allow your shoes to slide more easily.
Question: Are you likely to experience more friction walking on a surface covered in oil or water than on a dry surface? (A) Surface covered in oil or water (B) Dry surface (C) Oil friction.
Example Output:
B.