Jack is part of a team at XYZ Manufacturing. In his team meetings, at times, he understands and follows the discussion, and at other times he misses it because he is preoccupied with other thoughts. What can be the reason for Jack's inability to focus during team meetings?
1) Lack of interest in the discussion
2) Lack of understanding of the topic
3) Distractions from other thoughts
4) Physical discomfort during meetings