the triangle RST, we can measure the sides, and we get:
if we want the triangle ABC to be similar, has to be a right angle so the value of X has to be -2 or 3. let's see the triangles we have on each option:
So, triangles A and C have the same proportions that triangle RST, (half of each side)
so the correct option is between these two, now if we rotate the triangle RST, we get a similar triangle that A. (rotate until the side SR is vertical)
so the answer is: (-2,1)