Create a multiple choice question with three possible answers.
Which is the most abundant greenhouse gas in Earth's atmosphere?
a) Carbon dioxide
b) Water vapor
c) Methane
Complete the following task based on the instruction and optional input provided.### Instruction:
Create a multiple choice question with three possible answers.

### Output:
Which is the most abundant greenhouse gas in Earth's atmosphere?
a) Carbon dioxide
b) Water vapor
c) Methane