The following set of numbers is going to be graphed on a histogram.

3, 19, 11, 29, 4, 6, 10, 16, 2, 21, 15, 22, 13, 9, 1, 17, 2, 26, 18, 7

If there are going to be six intervals in the display, what is the length of each interval?

3
4
5
6