Given in the figure are two blocks A and B of weight 20 N and 100 N , respectively . These are being pressed against a wall by a force as shown in fig. If the coefficient of friction between the blocks is $0.1$ and between block B and the wall is $0.15$ , the frictional force applied by the wall on block B is

Question

$\begin{array}{1 1} 100\;N \\ 80\;N \\ 120\;N \\ 150\;N \end{array} $