A jet of liquid of cross-sectional area a strikes a wall making angle $\theta$ with the wall. The water strikes with the wall with velocity v and rebounds elastically. If density of liquid be $\rho$ the normal force on the wall is

• A

  $2{\mathrm{av}}^2\mathrm{\rho sin}\mathrm{\theta }$

• B

  $2{\mathrm{av}}^2\mathrm{\rho cos}\mathrm{\theta }$

• C

  $2av\mathrm{psin}\mathrm{\theta }$

• D

  $2\mathrm{av\rho cos}\mathrm{\theta }$