Answer:
im not sure but i think its b reconsider and look for other answers
Step-by-step explanation:
a
If m and n are parallel, then
∠ CBA = ∠ 2 ( alternate angles )
The sum of the 3 angles in a triangle = 180°, thus
∠ 1 + ∠ 2 + ∠ 3 = 180° ( sum of the angles in the triangle )
