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: Energy often changes from one form to another.
Sent 2: For example, the drummer transfers motion to sound energy.
Sent 3: When the moving drumstick strikes the drum head, the drum starts to vibrate.
Sent 4: The motion of the vibrating drum head creates the sound you hear.
Sent 5: Any form of energy can change into any other form.
Sent 6: Frequently, one form of energy changes into two or more different forms.
Sent 7: Have you ever sat in front of a campfire?
Sent 8: What are two things you notice?
Sent 9: The fire creates light.
Sent 10: It is also warm by the fire, meaning it creates heat.
Sent 11: The energy of the fire comes from the stored energy in the wood.
Sent 12: The wood contains chemical energy.
Sent 13: As it burns, the chemical energy is changed into light and heat.
Sent 14: Not all chemical energy changes produce light and heat.
Sent 15: Our cars use gasoline as a fuel.
Sent 16: Gasoline contains chemical energy.
Sent 17: When our cars burn gasoline in their engines, it is converted into motion and heat.
Sent 18: When energy changes forms, energy is conserved. 
Question: When you sit in front of a campfire, where does the energy of the fire come from? (A) Stored energy in the wood (B) It comes from the heat and light it produces (C) It comes from the light it gives out (D) Energy stored in the wood (E) It comes from the chemical energy it inherently possesses.
Answer:
A, D.