As we know that, Sl unit of following terms are (a) RH (Rydberg constant) =m−1 (b)h(Planck's constant) =J−s=kg−m2⋅s−2⋅s=kg−m2s−1 (c) Magnetic field energy density (µB)‌‌=‌
‌ Energy ‌
‌ Volume ‌
‌‌=‌
kg−m2s−2
m3
‌‌=kgm−1s−2 (d) η (coefficient of viscosity) ∵‌‌F=ηA‌
dv
dx
∴‌‌η=‌
Fdx
Adv
=‌
kg−ms−2⋅m
m2⋅ms−1
=kgm−1s−1 So, the correct match is A−3,B−2,C−4 and D-1.