Two blocks of mass M and m are connected with a string which passes over a smooth pulley as shown in fig. The mass M is placed on a rough 

inclined plane. The coefficient of friction between the block and the inclined plane is µ. What should be the minimum mass m so that the block M slides upward ?

• A

  $\mathrm{m}=\mathrm{M}(\sin \mathrm{\theta }+\mathrm{\mu cos}\mathrm{\theta })$

• B

  $\mathrm{m}=\mathrm{M}(\sin \mathrm{\theta }-\mathrm{\mu cos}\mathrm{\theta })$

• C

  $\mathrm{m}=\frac{\mathrm{M}}{(\sin \mathrm{\theta }+\mathrm{\mu cos}\mathrm{\theta })}$

• D

  $\mathrm{m}=\frac{\mathrm{M}}{(\sin \mathrm{\theta }-\mathrm{\mu cos}\mathrm{\theta })}$