If the general solution of the differential equation $\;y^{'}=\large\frac{y}{x} +\Phi (\large\frac{x}{y})\;$, for some function $\;\Phi\;$ , is given by $\;y ln |cx| = x\;$ , where c is an arbitrary constants , $\;\Phi(2)\;$ is equal to :

Question

$(a)\;4\qquad(b)\;\large\frac{1}{4}\qquad(c)\;-4\qquad(d)\;-\large\frac{1}{4}$