Can a player in a marked lane space break the vertical plane of any boundary line with a foot during a free throw?

During a free throw, players in the marked lane spaces must adhere to specific rules regarding their positioning. The correct understanding is that a player may break the vertical plane of the boundary line with a foot, but that foot must not touch the court outside the boundary. This means the player can extend their foot over the line as long as it doesn't land outside the playing area. This rule is in place to ensure that players maintain a fair position during the free throw process and do not gain an unfair advantage by crossing the boundary before the ball is shot.

The other choices do not accurately reflect these regulations. Options suggesting that players can break this plane without restrictions or must keep both feet inside do not adhere to the established guidelines governing free throw actions. Similarly, the notion that players can step outside as long as one foot remains inside is inconsistent with the rules limiting foot placement during the execution of free throws.