N bullets each of mass m kg are fired with a velocity \[v\,m{{s}^{-1}}\] at the rate of n bullets per second upon a wall. The reaction offered by the wall to the bullets is given by

• A.                         nmv              
• B.                         \[\frac{Nmv}{n}\]            
• C.                         \[n\frac{Nm}{v}\]                  
• D.                         \[n\frac{Nv}{m}\]