Instructions: In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.
Input: Question: In a three-point test crossover study, a negative interference indicates that:
Options: <1> More double crossings have occurred than expected. <2> There have been fewer double crossings than expected. <3> The match coefficient is less than 1. <4> A simple crossover decreases the likelihood of a double crossover occurring. <5> There have been fewer simple cross-links than expected.
Output:
1