Kira is using the figure shown to prove the Pythagorean theorem. She starts by writing the equation (a+b)^2 - c^2=4(1/2ab) because she knows two equal ways to represent the area of the shaded region. Which best describes the next steps Kira should take to complete her proof?
A. Simplify both sides of the equation to get a^2 + b^2 - c^2=2ab. Then subtract 2ab and add c^2 to both sides of the equation.
B. Simplify both sides of the equation to get a^2 + 2ab + b^2 - c^2 =2ab. Then subtract 2ab and add c^2 to both sides of the equation.
C. Simplify both sides of the equation to get a^2 + b^2 - c^2 = 2ab. Then add 2ab and c^2 to both sides of the equation.