SOLUTION
We want to select the reason why the triangles in the image are similar.
We can see that both triangles have two congruent sides, that is 3 and 1, and 2.25 and 0.75. They also have a common angle as shown below.
So, we can see two sides that are congruent and a common angle.
Hence the answer is side-angle-side theorem SAS, option B