In rapid mixing, what is the velocity gradient that will produced by $5KW$ mixer operation at $75\%$ efficiency. Consider the volume of the tank $=10m^3,($viscosity $=0\mathrm{.}001139N\frac{m}{s})$

A$.\frac{573}{s}$

B$.\frac{662}{s}$

C$.\frac{702}{s}$

D$.\frac{604}{s}$