(N/A) Magnetisation $(M)$ is defined as the magnetic moment per unit volume of a material.
Mathematically,$M = \frac{m_{net}}{V}$,where $m_{net}$ is the net magnetic moment and $V$ is the volume.
The $SI$ unit of magnetic moment $(m_{net})$ is $A \cdot m^2$ and the unit of volume $(V)$ is $m^3$.
Therefore,the $SI$ unit of magnetisation is $\frac{A \cdot m^2}{m^3} = A \cdot m^{-1}$ (Ampere per meter).
The dimensional formula of magnetic moment is $[M^0 L^2 T^0 I^1]$ and the dimensional formula of volume is $[M^0 L^3 T^0 I^0]$.
Thus,the dimensional formula of magnetisation is $\frac{[I^1 L^2]}{[L^3]} = [M^0 L^{-1} T^0 I^1]$.