I'll Give You Some Hints:
Let's Look at C.
In C, the triangle is translated 2 units to the right. Which means that it cannot be a reflection.
Let's Look at B.
In B there is a sideways triangle. That means it's a Rotation. Which means it's not Reflected.
Lastly, Let's Look at A.
To get from the original triangle to the triangle in A, you have to reflect twice. Once along a vertical line, and then along a horizontal line.
This Information Should Help You