instruction:
In this task, you are given a multiple-choice question and you have to pick the correct option. Answer with option indexes (i.e., "A", "B", "C", and "D").
question:
If something is in an ecosystem, it could be (A) invisible (B) vacuum of space (C) lacking life (D) alien
answer:
C


question:
Which of these could be a reason why the stars seem to be in a different place at dusk than at dawn? (A) rotation of the sky (B) rotation of the sun (C) rotation of the earth (D) rotation of the person
answer:
C


question:
Telephones will transfer acoustics using what energy (A) gamma radiation (B) heat transfer (C) electron flow (D) light pulses
answer:

C