The magnetic field $$B$$ produced by the current $$i$$ flowing through the sides of a square loop of side $$\ell$$, at a point $$P$$ at distance $$x$$ from the center of the square, on the axis perpendicular to the plane of the square loop and passing through its center, is

A

$$B = \frac{\mu_0i}{4\pi}\frac{2\sqrt{2}\ell^2}{\left(4x^2 + \ell^2\right)\sqrt{2x^2 + \ell^2}}$$

B

$$B = \frac{\mu_0i}{4\pi}\frac{4\sqrt{2}\ell x}{\left(x^2 + \ell^2\right)\sqrt{2x^2 + \ell^2}}$$

C

$$B = \frac{\mu_0i}{4\pi}\frac{8\sqrt{2}\ell^2}{\left(4x^2 + \ell^2\right)\sqrt{2x^2 + \ell^2}}$$

D

$$B = \frac{\mu_0i}{4\pi}\frac{4\sqrt{2}\ell x}{\left(4x^2 + \ell^2\right)\sqrt{x^2 + \ell^2}}$$