Which among the following is correct regarding diamagnetic materials?

A bar magnet of magnetic moment $M$ is placed at a distance $D$ with its axis along positive $X$-axis. Likewise, second bar magnet of magnetic moment $M$ is placed at a distance $2D$ on positive $Y$-axis and perpendicular to it as shown in the figure. The magnitude of magnetic field at the origin is $\left|\overrightarrow{B}\right|=\alpha \left[\frac{{\mu }_0}{4\pi }\frac{M}{D^3}\right]$. The value of $\alpha$ must be (Assume $D>>$ where $l$ is the length of magnets)