In fluid flow, and heat and mass transfer, one encounters (i) kinematic velocity (μ), (ii) molecular diffusivity (ζ) and thermal diffusivity (α). The units of these quantities are.

• A. μ , α and θ all have units of m/s
• B. μ , α and θ all have units of m2 /s
• C. α and θ have units of m2 /s, while μ has unit of m/s
• D. α and θ have units of m/s, while μ has unit of m2 /s