Justin and Amy are trying to prove the Triangle Angle Sum Theorem. Justin draws a triangle on a piece of paper, tears off the corners, and arranges them to form a line. Amy constructs a line through one vertex that is parallel to the opposite side and uses the Alternate Interior Angles Theorem to show that the interior angles add up to 180°. Who proved the theorem? Explain. (1 point) A Only Amy proved the theorem because she used postulates and theorems to construct a logical argument to show that the interior angles in a triangle add up to 180°.
B Only Justin proved the theorem because he demonstrated that the angles formed a line.
C Both Amy and Justin proved the theorem. Amy used postulates and theorems, while Justin used a demonstration.
D Neither Amy nor Justin proved the theorem.