Which of the following describes how a permanent can be destroyed?

The correct answer emphasizes that a permanent can primarily be destroyed by effects specifically using the term "destroy" or as a result of lethal damage. In the context of the game, "destroy" is a keyword that triggers effects that remove permanents from the battlefield, while lethal damage refers to damage equal to or exceeding a permanent's toughness. When a creature accumulates lethal damage, it is sent to the graveyard, demonstrating the principle that a permanent can fail to exist due to exceeding its toughness.

Other options provide context for how permanents might be removed from the battlefield, but they do not accurately encapsulate the mechanisms defined within the rules regarding destruction. Sacrificing a permanent is a different action entirely, as it does not involve the "destroy" effect, and counterspells specifically target spells on the stack, not permanents on the battlefield. Lastly, destruction is not limited to combat damage resolution; permanents can be destroyed at any time during a player's turn when a destroy effect is used or when damage reaches lethal levels. This reinforces that the essence of destruction in the game focuses primarily on the specific terminology and rules governing the nature of destruction.