求指导本题解题过程，谢谢您！18 单选 (4分)-|||-设L是平面上有向曲线,则下列曲线积分与路径无关的是 ()-|||-A. (int )_(1)^-(y)^2dx+(x)^3dy-|||-B. (int )_(1)^3y3(x)^2dx+(x)^3dy-|||-C. int (x)^3dx+3y(x)^2dy-|||-D. (int )_(1)^3y(x)^2dx-(x)^3dy

求指导本题解题过程，谢谢您！