Which equation could be used to solve for the measure of angle O?

Select one:

a. x + z = 180

b. x + y = 180

c. x - (y + z) = 360

d. x + y + z = 360

For the answer to the question above, the correct answer when the sum of the angles in the figure is 360 degrees. Option A or B would be the correct answer if the sum of the angles would be 180 degrees like in a triangle. Well, it depends on the position of the angle O. My best answer to your problem is a. x + z = 180