C

The S.I. unit of magnetic permeability (μ) is defined in terms of the magnetic field produced per unit current per unit length. Its unit is derived as follows:
Magnetic permeability is related to the magnetic field strength (H) in A/m and magnetic flux density (B) in T (Tesla). The relation is given by:
$$ B =  imes H $$
where $$  $$ (Tesla/Ampere-meter) is the permeability of free space (vacuum). Therefore, the unit of permeability (μ) is expressed as:
$$ ext{Unit of }  = rac{Tesla}{Ampere/meter} = rac{T}{A/m} = T imes rac{m}{A} = H/m $$ (since 1 T = 1 H/m).
Thus, the S.I. unit of magnetic permeability is Henry per meter, which corresponds to Option C: Henry.