The correct answer is A. Henry/meter.
Magnetic permeability is a measure of how easily a magnetic field can be established in a material. It is denoted by the Greek letter $\mu$ and has the SI unit of Henry per meter (H/m).
A Henry is the unit of inductance, which is the property of an electrical circuit that opposes any change in current. A meter is the unit of length. Therefore, a Henry per meter is a measure of how much inductance a material has per unit length.
The other options are incorrect. Henry is the unit of inductance, not magnetic permeability. Weber is the unit of magnetic flux, not magnetic permeability. Weber per meter is the unit of magnetic flux density, not magnetic permeability.