The dimensions of ≤ft(μ_0 ε_0)^-1 / 2 are:

$\left[L^{1 / 2} T^{-1 / 2}\right]$

$\left[L^{-1} T\right]$

$\left[L T^{-1}\right]$

$\left[L^{-1 / 2} T^{1 / 2}\right]$