The center-to-center spacing of horizontal ladder rungs for school-age children should be?

It is important to keep in mind that the center-to-center spacing of ladder rungs should be appropriate for the age and size of the children using it. While options A and B may seem reasonable, they do not leave enough room for children to safely and comfortably grip the rungs. On the other hand, option D may be too far apart for school-age children, making it difficult for them to climb. Option C, with a maximum spacing of 15 inches, strikes a balance between providing enough space for children to grip the rungs and being close enough for them to climb comfortably.