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: The model is designed to define average unit cost as a function of volume (Q), based on the USPS cost structure for FY 1999. Choices:  1. Q stands for price. 2. Q stands for the function of volume. 3. Q stands for the function of volume of mail delivered to homes.

1