Concept:The given differential equation can be solved by separating the variables and then integrating both sides.Explanation:Given: xdxdy=2y.Separating variables: ydy=x2dx.Integrating both sides: ∫ydy=∫x2dx.⇒logy=2logx+logc.⇒logy=logx2+logc.⇒logy=log(cx2).⇒y=cx2.This represents a family of parabolas with vertex at the origin and axis along the Y-axis.Answer:Option B: a family of parabolas with vertex at the origin and axis along the positive Y-axis.