点\(P\)为圆\(x^{2}+y^{2}=1\)与\(x\)轴正半轴的交点，将点\(P\)沿圆周逆时针旋转至\(P'\)，当转过的弧长为\(\dfrac{2}{3}π\)时，点\(P'\)的坐标为\((\quad)\)
A. \((\dfrac{1}{2},-\dfrac{\sqrt{3}}{2})\)
B. \((-\dfrac{1}{2},\dfrac{\sqrt{3}}{2})\) C. \((-\dfrac{\sqrt{3}}{2},\dfrac{1}{2})\) D. \((\dfrac{\sqrt{3}}{2},-\dfrac{1}{2})\)
