Sarah has a set of tiles that follow the pattern of the figures shown below. She says that she has a set of tiles that has nine red triangles. Is nine a reasonable number of red triangles? What is a valid explanation for your answer? The image consists of 3 separate figures. Figure 1 is a a square, within which is inscribed another square aligned so as to make each vertex touch the center of the side of the outer square. This inner square consists of 4 triangles, alternating between red and blue colour. Figure 2 has 2 such patterns, and figure 3 has 3 such patterns.

A. Yes; since Figure 3 has six red triangles, the next figure in the pattern will have nine red triangles.

B. Yes; since Figure 3 has six red triangles, and six and nine are both divisible by some whole-number factor n, the estimate is reasonable.

C. No; each tile has four triangles, so the number of red triangles for n tiles is 2n, which is divisible by four. Since nine is not divisible by four, it is not reasonable.

D. No; each tile has two red triangles, so the number of red triangles for n tiles is 2n, which is always even. Since nine is odd, it is not reasonable.