Definition: In this task, you're given a statement and three sentences as choices. Your job is to determine the neutral choice based on your inference from the statement and your commonsense knowledge. The neutral choice is a sentence that neither agrees nor disagrees with the statement. Indicate your answer as '1', '2', or '3', corresponding to the choice number of the selected sentence. If sentence X agrees with sentence Y, one's correctness follows from the other one. If sentence X disagrees with sentence Y, they can not be correct at the same time.
Input: Statement: The features of the six types of case study are not interchangeable. Choices: 1. The features of all six are interchangeable. 2. The six types of case study have features that are not interchangeable. 3. The features are case specific sometimes.

3