Answer:
C.
Explanation:
interior angles for ABCD is 360° and for ABO(triangle above) is 180°
from triangle,
you will get angle for OBA which is 180° - 38° - 90° = 52°
from angle B, we know that, straight line is 180°.
so,
180° = 52° +y- 12°
y = 140°
so, we can calculate x.
360° = 90° + 90° + 128° + x
x = 52°