A p H scale is shown, fading from red at the left end to blue at the right. Above the scale, p O H is shown in even increments from 14 to zero, and below the scale, p H is shown in even increments from 0 to 14. Points marked are: A at 1 on the p H scale, B at 7 on the p O H scale, C at 13 on the p H scale, and D at 6 on the p H scale. Based on log rules and the way pH is calculated, what is the difference in [OH– ] concentration between point A and point B