Explanation:
Hey there!
Your answer is Option B and C.
For option B: the exterior angle is equal to sum of two opposite interior angles. (theorem of triangle).
For Option C: angle 4 and angle 3 is 180° (i.e angle 3 + angle 4 = 180°) Or (angle 4= 180°-angle 3).
Therefore, answer: Option B and C.
Hope it helps...