What happens if a batter leaves the batter's box without permission and a pitch is delivered?

When a batter leaves the batter's box without getting the proper permission and a pitch is delivered, a strike is called on the batter. This rule is in place to maintain the integrity of the game and ensure that all players are ready to participate when a pitch is thrown.

The rationale behind this rule is that the batter must be prepared and in position to face the pitch; leaving the box prematurely can disrupt the flow of the game. Umpires are trained to enforce this rule to keep the game moving, so the act of stepping out without permission directly results in a penalty against the batter.

In contrast, the other options do not align with the established rules of softball regarding a batter's positioning and readiness. For instance, declaring the pitch a no-pitch or resetting the at-bat does not reflect the consequences of stepping out of the box without permission, as these situations do not account for the established rules intended to manage gameplay.