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: (Note that this C-R function is based on the original air quality dataset used in the ACS study, covering 50 cities, and used the median PM2. Choices:  1. The mean of PM2 is used in the function. 2. A total of 50 cities were tested for the original air quality dataset. 3. Each of the 50 cities were also ranked for air quality from worst to best.

1