In Figure, coefficient of friction between the block and the floor is ‘µ’. Force F that will move the block on the floor with a uniform speed is 

• A

  $(\mathrm{\mu sin}\mathrm{\theta }+\cos \mathrm{\theta })\mathrm{mg}$

• B

  $(\mathrm{\mu sin}\mathrm{\theta }-\cos \mathrm{\theta })\mathrm{mg}$

• C

  $\frac{\mathrm{\mu mg}}{\cos \mathrm{\theta }-\mathrm{\mu sin}\mathrm{\theta }}$

• D

  $\frac{\mathrm{\mu mg}}{\sin \mathrm{\theta }-\mathrm{\mu cos}\mathrm{\theta }}$