A.\({x^2} - \cos x + \dfrac{1}{5}\sin 5x - 1\)
B.\({x^2} + \cos x - \dfrac{1}{5}\sin 5x + 2\)
C.\({x^2} + \cos x - \dfrac{1}{5}\sin 5x - 2\)
D.\({x^2} - \cos x + \dfrac{1}{5}\sin 5x + 1\)