To support Mason's claim that a parallelogram can be cut into two right scalene triangles, you would need a diagram showing a parallelogram with a diagonal splitting it in half. This is because cutting a parallelogram along one of its diagonals will create two triangles.
However, it's important to note that while the triangles created by cutting a general parallelogram would indeed be triangles, they may not necessarily be "right scalene triangles" unless the angles and side lengths meet those specific criteria (one angle is 90 degrees, and all sides are of different lengths).
The best response would be:
Parallelogram with a diagonal splitting the figure in half.
This diagram is the only one that directly supports the action described in Mason's claim.