What defines a legal set position for a pitcher?

A legal set position for a pitcher involves specific positioning that ensures the pitch must be delivered in a fair and controlled manner. When the pivot foot completely covers the pitcher's plate, it establishes that the pitcher is properly balanced and ready to deliver the pitch. This requirement helps maintain fairness and safety by ensuring the pitcher is in a position to make a controlled and legitimate pitch toward the batter.

The other options, while they may describe certain aspects of the pitching rules, do not accurately define the fundamental criteria of a legal set position. For instance, the non-pivot foot doesn't necessarily have to be behind the plate, as long as the pivot foot is correctly positioned. Likewise, while a pitcher may benefit from facing the batter, it is not a formal requirement for the set position to be considered legal. The emphasis remains on the pivot foot's placement covering the pitching plate to ensure compliance with the regulations governing pitching.