ANS:C - permeability of free space.

The unit Tesla meter per ampere (T·m/A) is the unit for the measurement of permeability of free space. Permeability of free space (μ0​) is a physical constant that describes the ability of a material to allow magnetic fields to pass through it. It is a fundamental property of vacuum or free space and is approximately equal to 4π×10−7 henrys per meter (H/m) in the International System of Units (SI). The unit Tesla meter per ampere (T·m/A) represents the SI unit of magnetic permeability. It indicates the magnitude of the magnetic field (B) produced by a current (I) flowing through a conductor, as described by Ampère's law: B=μ0​⋅I where:

• B is the magnetic flux density (measured in teslas, T),
• μ0​ is the permeability of free space (measured in T·m/A),
• I is the current (measured in amperes, A).