Definition: In this task, you're given a statement, and three sentences as choices. Your job is to determine which sentence clearly disagrees with the statement. Indicate your answer as '1', '2', or '3' corresponding to the choice number of the selected sentence.
Input: Statement: Power generators are a significant source of three key  sulfur dioxide (SO2), nitrogen oxide (NOx), and mercury (Hg). Choices:  1. The power generators are the only source for mercury. 2. The power generators make a lot of sulfur dioxide. 3. The power generators are bad for the environment.

1