Which of the following is an example of "visual representation"?

Visual representation in the context of Magic: The Gathering refers to aspects of the game that can be clearly observed and interpreted by players, often through physical placement or arrangement of game components. Zone changes illustrate this concept well, as they represent changes in the location of cards within the game, such as moving a card from the battlefield to the graveyard or from the hand to the library. These changes are visually evident, allowing players and judges alike to understand the state of the game at a glance.

The other options—player's hand size, deck composition, and sideboard cards—do not fit as clearly within the definition of visual representation. While they are important aspects of the game, they generally require more information or a deeper understanding to interpret fully. For example, the player's hand size may need to be assessed verbally or represented by the cards in hand, and deck composition might require a decklist to understand fully. Sideboard cards are similarly reliant on external knowledge about the match and the deck strategy rather than being directly observable in the same way that zone changes are.