What items must you have with you during the check-in process?

The correct choice emphasizes the necessity of having a photo identification during the check-in process. A photo ID serves as a crucial means of identification, confirming the identity of the participant and ensuring that only authorized individuals can access the event. This is important for maintaining security, verifying registration details, and ensuring a smooth check-in experience.

While having event guidelines is also valuable for understanding the rules and structure of the event, the primary focus during check-in is to authenticate participants visually and through documentation, which is why a photo ID is indispensable. Other items like a phone may not be essential during the check-in phase, and the event guidelines can be consulted later once the participant is inside the venue.