What core material property determines the inductance of an inductor?

Explanation

Permeability measures how readily a material carries magnetic flux, and inductance is directly proportional to it, as in L = μ₀ × μ_r × N² × A / l for a uniformly wound core. Permittivity is the corresponding property for electric fields in capacitors, resistance is not what sets inductance, and reactivity is not a material parameter.