Coordinate Geometry: JEE Main 2026 Mathematics question

Let O be the vertex of the parabola $x^2=4y$ and Q be any point on it. Let the locus of the point P, which divides the line segment OQ internally in the ratio $2:3$ be the conic C. Then the equation of the chord of C, which is bisected at the point $(1,2)$, is :