When is it necessary for a player to shuffle their deck?

A player is required to shuffle their deck after presenting it to their opponent before a match or when instructed by the rules. This process serves several important functions. It ensures that the deck is randomized and that neither player has any predictable patterns or advantages based on the order of the cards. By shuffling, players uphold integrity and fairness in the game, as randomization is a critical part of card-based events.

The game's rules are designed to maintain a level playing field, and shuffling at these specified times helps prevent any potential manipulations or premeditated card arrangements. Additionally, if a player is specifically instructed to shuffle during a match or event, it is their responsibility to comply to ensure the game stays fair and conducted according to the established guidelines.

The other options describe circumstances that do not directly invoke a requirement to shuffle in the same way, making them less appropriate in the context of when shuffling is necessary according to the rules.