There are 2 solutions because the line x+2y = 12 and the circle intersect at two locations. One point of intersection is (0,6). So this suggests choice B is the answer; however, the point (12,0) is not a solution.
It works for x+2y = 12 since 12+2(0) = 12. But the point (12,0) is not on the circle. The furthest to the right we go is (6,0).
21.59-13.09= 8.5 cm if its centered, it will same distance from the margin from the left and right. So its distance from left or right margin is 8.5/2 = 4.25 cm