A block of mass m is pulled along a horizontal surface by applying a force at an angle $\theta$ with the horizontal. If the block travels with a uniform velocity and has a displacement d and the coefficient of friction is $\mu$, then the work done by the applied force is

• A

  $\frac{\mu mgd}{\cos \theta +\mu \sin \theta }$

• B

  $\frac{\mu mgd\cos \theta }{\cos \theta +\mu \sin \theta }$

• C

  $\frac{\mu mgd\sin \theta }{\cos \theta +\mu \sin \theta }$

• D

  $\frac{\mu mgd\cos \theta }{\cos \theta -\mu \sin \theta }$