C: reflection then rotation.
Extra Info:
Dilation is when the shape changes in size, which doesn't happen.
Translation is when it just moves across. It may look like that is happening here, but I'll explain.
The triangle is first reflected along the line [tex]x=0[/tex]. Imaging putting a mirror on the x=0 line (the y axis, basically), and you'd see 1 to 2.
Then, it is rotated around the point [tex](0,0)[/tex]. Get a bit of tracing paper, draw over 2, and then, holding the tracing paper down at [tex](0,0)[/tex] (works well with a pencil), rotate it round and you will find it fits perfectly over 3.
