What is permitted to designate the center restraining circle?

The center restraining circle can be designated by contrasting colored-floor areas. This allows for clear visibility and identification of the circle during gameplay. By using contrasting colors, officials and players can easily recognize the boundaries of the restraining circle, which is important for ensuring all players adhere to the rules regarding positioning during the jump ball and other game situations.

The other options present specific measurements for lines, which are not permitted according to NFHS basketball regulations. The requirement for the center restraining circle emphasizes usability and clarity on the court, which contrasting color provides more effectively than a line of any specific width. The implementation of contrasting colors helps to maintain the integrity of the game by minimizing confusion and making the playing area easily interpretable for all participants.