It's the fourth answer, y=10. This is because the line is a straigh line is 180 degrees, which is shown in the photo. You have to take away 120 degrees (the angle is the same on both sides) which would leave you with 60. Then, thats the sum of the angle, but since were solving for y, you have to divide 60 by 6, which gives you your answer, 10. Hope this helps, if you need anything else you can message me!
