Two point charges, \(+q\) and \(-q\), are held fixed on the \(y\)-axis at \((0, a)\) and \((0, -a)\), respectively, in vacuum.

Point \(P\) is located on the positive \(x\)-axis at a distance \(x\) from the origin.

Which of the following correctly gives the net electric field vector \(\vec{E}(x)\) at point \(P\) and the power-law exponent \(n\) describing the asymptotic dependence of its magnitude, \(E(x) \propto x^n\), in the limit \(x \gg a\)?