1. Find the SI units of each quantity in List-I

(a) $R_H$ : Rydberg constant

The Rydberg constant appears in spectroscopy equations like $\frac{1}{\lambda}=R_H\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)$ Since $1/\lambda$ has unit of inverse length, $[R_H]=m^{-1}$ So, $(a) \to (iii)$

(b) $h$ : Planck's constant

From $E=h\nu$ we have $[h]=\frac{[E]}{[\nu]}=\frac{kg\,m^2\,s^{-2}}{s^{-1}}=kg\,m^2\,s^{-1}$ So, $(b) \to (ii)$

(c) $\mu_B$ : Magnetic field energy density

The quantity intended here matches magnetic field energy density, whose unit is $\text{energy density} = \frac{J}{m^3} = \frac{kg\,m^2\,s^{-2}}{m^3}=kg\,m^{-1}\,s^{-2}$ So, $(c) \to (iv)$

(d) $\eta$ : coefficient of viscosity

Dynamic viscosity has SI unit $Pa\cdot s = (N/m^2)\cdot s$ Now, $Pa = \frac{N}{m^2}=\frac{kg\,m\,s^{-2}}{m^2}=kg\,m^{-1}\,s^{-2}$ Hence, $[\eta]=kg\,m^{-1}\,s^{-2}\cdot s = kg\,m^{-1}\,s^{-1}$ So, $(d) \to (i)$

2. Final matching

$(a)-(iii),\quad (b)-(ii),\quad (c)-(iv),\quad (d)-(i)$

This corresponds to Option B.

3. Comparison with stored correct answer

Stored correct answer = B

Our derived answer = B

So, the derived answer agrees with the stored answer.