The correct option is A ϕ(x2+y2,y2−yz)=0
y2p−xyq=x(z−2y)
On comparision with P.p+Qq=R
P=y2,Q=−xy,R=x(z−2y)
By Lagrange's Auxiliary equation
dxP=dyQ=dzR
i.e., dxy2(I)=dy−xy(II)=dzx(z−2y)(III)=xdx+ydy0(IV)
Taking I and IV, dxy2=xdx+ydy0
⇒xdx+ydy=0
i.e.,x2+y2+C1
Again By II and III, dy−xy=dzx(z−2y)
zdy−2ydy=−ydz
or ydz+zdy=2ydyord(yz)=d(y2)
i.e., yz−y2=C or y2−yz=C2
So General solution is ϕ(C1,C2)=0
⇒ϕ(x2+y2,y2−yz)=0