A.\(\int {f\left( x \right)dx}  = {x^3} - {x^2} + x + C\)
B.\(\int {f\left( x \right)dx}  = 3{x^3} - 2{x^2} + x + C\)
C.\(\int {f\left( x \right)dx}  = 6{x^3} - 4{x^2} + 2x + C\)
D.\(\int {f\left( x \right)dx}  = \frac{{{x^3}}}{3} - \frac{{{x^2}}}{2} + x + C\)