Given the setup shown in Fig Block `A, B` and `C` have masses `m_(A)= M` and `m_(B) =m_(C) = m`. The strings are assumed maseless and unstreichable, and the pulleys frictionless .There is no friction between block `B` and the support table, but there is friction between blocks `B` and `C`, denoted by a given coefficient `mu`

a . In terms the given find (i) the acceleration of block `A` and `B`
b. Suppose the system is released from rest with block `C` near the right end of block `B` as shown in the above figure. If the the length `L` of block `B` is given, what is the speed of block `C` as it reached the left end of block `B` ? Tear the size of `C` as small
c. If the mass of block `A` is less then some critical value, the blocks will not accelerate when released from rest. Write down as expression for that critical mass.