Which rules govern how matches are paired in a tournament?

The correct answer focuses on the specific guidelines that establish how matches are organized and paired in a tournament setting. The tournament pairings guidelines are a crucial facet of tournament structure, ensuring that players are matched appropriately based on their records and other relevant criteria. These guidelines provide the framework for how players with similar standings face off against each other, promoting fair competition and a rewarding tournament experience.

The other options, while related to various aspects of tournament play, do not specifically address the pairing of matches. Matchmaking regulations might imply rules for pairing but are not the official terminology used in the context of tournament guidelines in the Magic: The Gathering community. Deck-building policies refer to the composition of players' decks and do not pertain to how matches are organized. Game format instructions provide rules for how games are played within a specific format but do not involve the logistics of pairing participants in a tournament setting. Hence, tournament pairings guidelines are the definitive source for understanding match organization in competitive play.