(c)
Given, $\frac{dy}{dx} = 2\ \frac{y}{x}$ $(\therefore y = mx)$
$\Rightarrow$ $\int_{}^{}\frac{dy}{y} = 2\int_{}^{}\frac{dx}{x}$
$\Rightarrow$ $\log y = 2\log x + \log c$
$\Rightarrow$ $y = cx^{2}$
Which represent a parabola of the form
$x^{2} = 4ay$