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

Question

( A ) both the scales read M kg each
( B ) the scale of the lower one reads M kg and of the upper one zero
( C ) the reading of the two scales can be anything but the sum of the readings will be M kg
( D ) both the scale read M/2 kg