B. 100
Explanation:
If you just look at it like a straight line then you know it equals 180° but since it’s cut into pieces we have to figure out the others first.
So on the triangle on the bottom it’s 50 and 50 so add those and subtract from 180 to find out what the third angle in the triangle is.
50+50=100
180-100= 80°
Now the angle to the right of the 60° is going to be 80 because they’re corresponding.
So, if the one side of the split line is 80 then the other must be 100°.