Three blocks l, 2 and 3 are arranged as shown in the figure. The velocities of the blocks ${\mathrm{v}}_1, {\mathrm{v}}_{2 }\mathrm{and} {\mathrm{v}}_3$ are shown in the figure. What is the relationship befween ${\mathrm{v}}_1, {\mathrm{v}}_2 \mathrm{and} {\mathrm{v}}_3$?

• A

  $2{\mathrm{v}}_1+{\mathrm{v}}_2 = {\mathrm{v}}_3$

• B

  ${\mathrm{v}}_1+{\mathrm{v}}_2 = {\mathrm{v}}_3$

• C

  ${\mathrm{v}}_1+ 2{\mathrm{v}}_2 = {\mathrm{v}}_3$

• D

  None of these