Dilation changes the size of the shape (how big or small the shape is), rather then changing the shape itself (into a completely different shape). The other options are transformations, but they only move the shape along the graph, nothing else. Hope this helps!
If it’s a right triangle 1 side is a right angle and if those 2 sides are equal and not right angles then E needs to be a right angle and a right angle is 90 degrees so it’s D
