What action should an umpire take if a coach bumps into him during a discussion?

In the context of managing interactions on the field, when a coach bumps into an umpire during a discussion, the umpire must maintain authority and ensure the game's integrity. Ejecting the coach immediately is appropriate, as physical contact, even if unintentional, can signify a lack of respect for the authority of the umpire.

By choosing to eject the coach, the umpire sends a clear message that physical interactions between coaches and officials are unacceptable and must be addressed to maintain a respectful environment. The umpire’s role is crucial in setting a tone of professionalism and ensuring all participants understand the boundaries of acceptable behavior. This action emphasizes the importance of upholding the standards of the game and discourages any potential escalation of the situation that could arise from ignoring the incident or allowing the coach to continue without a consequence.

In this scenario, the other choices would not adequately address the seriousness of the contact, potentially leading to further confrontations and undermining the umpire's authority.