Discs weighing 20kg and over must not exceed what thickness in centimeters?

The correct answer reflects a specific regulation within the standards set by the International Powerlifting Federation (IPF) regarding the maximum thickness of weight discs that weigh 20 kg and over. According to IPF guidelines, discs that weigh 20 kg or more must not exceed a thickness of 6 cm. This limit is in place to ensure uniformity and safety in competition, as thicker discs could lead to variations in how weights are lifted and an uneven surface during the lift.

Having a standard maximum thickness helps in maintaining a level playing field for all competitors, allows for better handling and positioning of the weights on the bar, and promotes safety during lifts. This regulation is critical for the integrity of the sport and the safety of the athletes involved.

The other options present different thicknesses, which do not align with the established IPF guidelines for discs of this weight category. Therefore, choosing 6 cm as the correct maximum thickness aligns with the rules set by the governing body of powerlifting competitions.