○=> Correct option :

○=> Steps to derive correct option :
Sum of all angles in a quadrilateral = 360°
Given :
▪︎Measure of angle U in quadrilateral RSTU = 80°
We know that corresponding angles in a quadrilateral are equal.
Which means :
▪︎Angle U = Angle y
Thus, the measure of angle y = 80°
Angle T = angle x (corresponding angles of a quadrilateral are equal)
Let us name angle T and angle x together as 2x.
Which means :





Thus, the measure of angle x = 100°
Therefore, the correct option is (a) y = 80, x = 100