Which is NOT required for a pitcher to be in a legal pitching position?

The foot that maintains contact with the pitcher's plate, absorbs the body's weight, pushes off against the plate during the initial step phase of the pitch, and drags along the ground during the final phase of the pitch.

Before starting a pitch, the pitcher must comply with the following:

The pitch officially begins and cannot be discontinued once the hands have separated after coming together.

Pitcher becomes airborne on the initial drive from the pitcher's plate. The pivot foot does not slide/drag on the ground.

The pitcher hops or drags to replant, gain a second starting point and push off their pivot foot. The pivot foot bears weight a second time before the release of the pitch.

A pitch that violates the pitching rules.

On an Illegal Pitch:

If the batter reaches first base safely and each other base runner advances at least one base, the play stands, and the illegal pitch is canceled.

A pitch that is intended to catch the batter off balance or otherwise unprepared to bat, shall be ruled...

What is the only legal way for a pitcher to discontinue a pitch after stepping on the pitcher's plate?

The pitcher is required to wipe off any substance applied to her hands or fingers if it would transfer to the ball. This includes all of the following except:

If, in the umpire's judgment, a pitcher intentionally pitches at a batter, the umpire shall warn all of the following EXCEPT:

All pitches must be legally pitched to the catcher in order to intentionally walk a batter, and runners may advance at their own risk of being put out.

How long does the pitcher have to be on the pitcher's plate, the catcher have to be in the catcher's box, and the batter to be in the batter's box?

After the pitcher, catcher, and batter are in position, how long does the pitcher have to bring their hands together?

How long does the pitcher have to deliver the pitch after bringing her hands together?

After a pitching change not necessitated by an injury to the replaced pitcher, a relief pitcher may throw not more than how many warm up pitches?

How many warm up pitches can a pitcher throw if she returns to pitch in an inning in which she has already pitched?

How many warm up throws can a pitcher throw to first base in any given situation?