tension Questions

A light spring balance hangs from the hook of the other light spring balance and a block of mass $M\text{kg}$ hangs from the former one. Then the true statement about scale reading is:

A block of mass $M$ is pulled along a horizontal friction surface by a rope of mass $m$. If a force $P$ is applied at the free end of the rope, the force exerted by the rope on the block is: