Three blocks are initially placed as shown in the figure. Block `A` has mass `m` and initial velocity `v` to the right. Block `B` with mass `m` and block `C` with mass `4m` are both initially at rest. Neglect friction. All collisions are elastic. The final velocity of blocks `A` is
A. `0.6 upsilon` to the left
B. `1.4 upsilon` to the left
C. `upsilon` to the left
D. `0.4 upsilon` to the right