Chapter 9, Problem 132P

Which choice is the genera1 differential equation form of the continuity equation for a control volume?
   ${\displaystyle \underset{CS}{\int }\rho \stackrel{\to }{V}\cdot \stackrel{\to }{n}dA=0}$

   ${\displaystyle \underset{CV}{\int }\frac{\partial \rho }{\partial t}dV}+{\displaystyle \underset{Cs}{\int }\rho \stackrel{\to }{V}\cdot \stackrel{\to }{n}dA=0}$

   $\stackrel{\to }{\nabla }\cdot \left(\rho \stackrel{\to }{V}\right)=0$

   $\frac{\partial \rho }{\partial t}+\stackrel{\to }{\nabla }\cdot \left(\rho \stackrel{\to }{V}\right)=0$

1. None of these