Which of the following states the pythagorean theorem? . a. for an isosceles triangle, if a, b, c are the sides of the triangle with c being the hypotenuse, then a^2+b^2=c^2. b. for an acute triangle, if a, b, and c are the sides of the triangle with c being the hypotenuse, then a^2+b^2=c^2. c. for an obtuse triangle, if a, b, and c are the sides of the triangle with c being the hypotenuse, then a^2+b^2=c^2. d. for a right triangle, if a, b, and c are the sides of the triangle with c being the hypotenuse, then a^2+b^2+c^2