Galina is finding the area of triangle RST. To do so, she follows the steps in the table.

Step 1 Draw a rectangle around triangle RST.
Step 2
Find the area of the rectangle.

Step 3 Find the area of the three right triangles created
by the sides of the rectangle and the intersection
with each vertex of the triangle.
Step 4
Subtract the area of the right triangles from
the area of the rectangle.

To solve the problem using these steps, what are the dimensions of the rectangle she should draw?

On a coordinate plane, triangle R S T has points (negative 1, 1), (1, 3), and (2, negative 1).

2 units by 4 units
3 units by 4 units
3 units by 5 units
4 units by 5 units