Answer:
Options B and D are true.
Step-by-step explanation:
See the diagram attached.
Line a and b are parallel and line c is not parallel to them.
There is a transverse line and this line forms the angles 1 to 12.
Now, option A gives ∠ 8 + ∠ 10 = 180° which can not be true as line c is not parallel to line b.
Option B gives ∠4 + ∠ 6 = 180° which is true because line a is parallel to line b and ∠ 4 and ∠ 6 are interior supplementary angles.
Option C gives ∠ 1 + ∠ 11 = 180° which can not be true as line c is not parallel to line a.
Option D gives ∠3 + ∠ 5 = 180° which is true because line a is parallel to line b and ∠ 3 and ∠ 5 are interior supplementary angles.
Therefore, options B and D are true. (Answer)
