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").

Which of the following has a population of zero? (A) Merriam's elk (B) bison (C) llama (D) whooping crane
A

A light using energy can cease that activity when (A) light bulbs are gold (B) lights are always on (C) wall switch is adjusted (D) walls are painted blue
C

When did the pond have less heat energy? (A) when people sat by it (B) when people skated on it (C) when people fished in it (D) when people swam in it

B