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.

Let me give you an example: Paragraph- Sent 1: Obama was born on August 4, 1961, at Kapiʻolani Maternity & Gynecological Hospital in Honolulu, Hawaii.
Sent 2: He is the only President to have been born in Hawaii.
Sent 3: He was born to a white mother and a black father.
Sent 4: His mother, Ann Dunham (1942-1995), was born in Wichita, Kansas, of mostly English descent, with some German, Irish, Scottish, Swiss, and Welsh ancestry. Question: How old was Obama's mother when he was born? (A) teenager (B) in his 40s (C) mid 20s (D) almost twenty.
The answer to this example can be: D.
Here is why: Obama was born in 1961. His mother was born in 1942 and 1961-1942=19. Therefore, "almost twenty" answers the question sufficiently.

OK. solve this:
Paragraph- Sent 1: Magnets are able to place a force on certain materials.
Sent 2: This force is called a magnetic force.
Sent 3: The force a magnet exerts is a little different from the forces you may normally think about.
Sent 4: You exert a force on a book when you lift it.
Sent 5: You also exert a force on the pedals of your bicycle.
Sent 6: In both those cases, those forces cause a change.
Sent 7: The change you see in both these cases is called motion.
Sent 8: Magnets, too, can produce change.
Sent 9: They can produce motion just like you do.
Sent 10: Unlike you, magnets do not have to touch something to exert a force.
Sent 11: A magnetic force is exerted over a distance.
Sent 12: Thats right, a magnet can push or pull certain items without ever touching them.
Sent 13: Thats how the maglev train works.
Sent 14: Do you know another type of force that does not require objects to touch?
Sent 15: These forces are known as non-contact forces.
Sent 16: Another type of non-contact force you may be familiar with is gravity.
Sent 17: Gravity too can cause changes in motion.
Sent 18: Gravity holds our moon in orbit without touching it. 
Question: Can magnets produce motion? (A) No,  they can only produce change (B) No (C) Yes,  they can.
Answer:
C.