Answer:
B. 43
Explanation:
ignore the other triangle with the y angle. it is just there to confuse us.
the main information is given already by the main triangle with the angles x and 47 degrees.
because it's baseline is the diameter of a circle, and its top point is also on the circumference of the same circle.
all triangles that can be inscribed into a circle that way are by definition right-angled triangles.
so, the angle at the top point is actually 90 degrees.
and as we know, the sum of all angles in a triangle is always 180 degrees, we can simply calculate :
180 = 90 + 47 + x = 137 + x
x = 43 degrees
that's it.