A unimodal permutation of length n is an arrangement of the numbers 1 through n in such a way that the numbers increase up to a point and decrease after that and each number is used exactly once. For example: (2, 3, 5, 6, 4, 1) is a unimodal permutation of length 6. (3, 6, 7, 5, 4, 2, 1) is a unimodal permutation of length 7.

An unknown number x is at most 10. which graph best represents all the values of x? number line graph with closed circle on 10 and shading to the right. number line graph with open circle on 10 and shading to the right. number line graph with open circle on 10 and shading to the left. number line graph with closed circle on 10 and shading to the left.