The SI unit of magnetic susceptibility is

The correct answer is Option (2) → It has no unit

NCERT (2026-27):
Magnetisation and Magnetic Intensity – “… where H has the same dimensions as M and is measured in units of A m^–1. … This influence is mathematically expressed as

    \( \mathbf{M}=\chi\mathbf{H} \qquad (5.13) \)

where \( \chi \), a dimensionless quantity, is appropriately called the magnetic susceptibility.”