which combination of figures are similar and why

A.figure 1,figure 2 and figure 3 all figures are rectangles
B.figure 2 and figure 3 the figures are both vertical
C.figure 1 and figure 2 the side lengths are proportional and corresponding angels are equal
D.figure 1 and figure 3;one figure is larger than the other

C. Figure 1 and figure 2 are similar because the side lengths are proportional and corresponding angles are equal. This means that the two figures have the same shape, but one is a scaled-up or scaled-down version of the other.