The vector potential A due to a magnetic moment m at a point r is given by A = \(\frac{m\times r}{r^3}\). If m is directed along the positive z-axis, the x-component of the magnetic field, at the point r, is
1
\(\frac{3myz}{r^3}\)
2
\(-\frac{3myz}{r^3}\)
3
\(\frac{3mxz}{r^5}\)
4
\(\frac{3m(z^2-xy)}{r^5}\)