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: Therefore, it may be possible for a fairly simple model to explain total and unit cost differences between posts. Choices:  1. There is no need for a complex model for explaining cost differences between posts. 2. Simple models have always been used for explaining cost differences between posts. 3. The cost differences between posts require a very intricate model for explaining them.

3