In the diagram, P, Q, R and S are points on the circle with centre O and PQR = 104^. Find the angle marked y.

The points $P, Q, R, S$ lie on the circle, making $PQRS$ a cyclic quadrilateral. In a cyclic quadrilateral, opposite angles sum to $180^\circ$.

Angle $\angle PQR$ and $\angle PSR$ are opposite angles in the cyclic quadrilateral $PQRS$.

The angle at the center, $\angle POR$ (marked as $y$), and the angle at the circumference, $\angle PSR$, both subtend the same arc $PR$. The angle at the center is twice the angle at the circumference subtended by the same arc.

The angle marked $y$ is \boxed{\text{152^\circ}}.
This corresponds to option A.