Solution of the differential equation $x d y-y d x=0$ represents

a rectangular hyperbola a straight line passing through the origin parabola whose vertex is at the origin circle whose centre is at the origin

a straight line passing through the origin

$xdy-ydx=0$ so $\frac{xdy-ydx}{x^2}=0$ so $\int d(\frac{y}{x})=\int 0dx$ so $\frac{y}{x}=C$ so $y=Cx$