In the given arrangement of a doubly inclined plane two blocks of masses $M$ and $m$ are placed. The blocks are connected by a light string passing over an ideal pulley as shown. The coefficient of friction between the surface of the plane and the blocks is $0.25$. The value of $m$, for which $M=10 \mathrm{kg}$ will move down with an acceleration of $2 \mathrm{m} {\mathrm{s}}^{-2}$, is: (take $g=10 \mathrm{m} {\mathrm{s}}^{-2}$ and $\tan 37°=\frac{3}{4}$)

• A

  $9 \mathrm{kg}$
• Correct answer
  B

  $4.5 \mathrm{kg}$
• C

  $6.5 \mathrm{kg}$
• D

  $2.25 \mathrm{kg}$

Hence, the correct answer is option: 'B'.