The correct option is B Are orthogonal
For the family of curves represented by the first differential equation the slope of the tangent at any point C1(x,y) is given by (dydx)c1=x2+x+1y2+y+1
For the family of curves represented by the second differential the slope of the tangent at any point is given by
(dydx)c1=−y2+y+1x2+x+1
Clearly, (dydx)c1×(dydx)c1=−1
Hence, the two curves are orthogonal.