Detailed Instructions: 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.
Q: Statement: Nobody knew whether there was life on Mars because, oddly enough, nobody had looked until now. Choices: 1. There was life on Mars. 2. Scientists have checked for life on Mars before. 3. If was unknown as whether their was life on Mars or not.
A:
2