Which of the following statements best describes the conserv…

Which of the following statements best describes the conservation of mass for a steady flow system? A) The net mass flow rate into and out of a control volume is zero, meaning the total mass entering equals the total mass leaving. B) The mass flow rate into a control volume must always be greater than the mass flow rate out. C) The density of the fluid must always change within the control volume for conservation of mass to hold. D) For an incompressible fluid, the sum of the velocity flow rates at the inlet must be greater than at the outlet.