C is the correct answer I think
The scale factor is 1/3.
To find this scale factor, choose a set of sides to compare lengths. For example, taking the left sides of the triangles, which is 9 and 3. 9 is 3 times bigger than the triangle on the right, so that gives us the scale factor of 1/3.
Are you rounding to the nearest 100’s place?
2/5 is bigger and 3/8 is smaller